五、發明說明（1) 詳細說明： (發明所屬之技術領域） 本發明係關於室溫時之帶隙爲2.8電子伏特（electron vo It) (eV)以上3.4eV以下之磷化硼（BP)層或含有磷化硼 並以一般式 BaAlpGaYIm-a_卜YPsAseNm(〇<〇^l，〇M<l， 〇$γ<1，0<α + β + γ$1，0<δ$1，0$ε<1，0<δ + ε$1)記述之磷 化硼（ΒΡ)系混晶層，具備這些ΒΡ層或ΒΡ系混晶層之半 導體元件，及這些BP層或BP系混晶層之製造方法。 (以往技術） 由屬於元素週期表之III之硼（B)和V族之元素作成之 ΠΙ-V族化合物半導體有氮化硼（BN)，磷化硼（BP)和砷 化硼（BAs)。例如，六面體晶之氮化硼（ΒΝ)係爲室溫時 之帶隙（band gap)爲7.5電子伏特（eV)之間接遷移型半導 體（參照（培風館（公司），1 995年3月30日發明初版，寺 本嚴著「半導體裝置槪論」第28頁）。砷化硼（BAs)熟 知係爲室溫時之帶隙約爲〇.85eV之間接遷移型之in-v 族化合物。（參照上述之「半導體裝置槪論」）。 另外，磷化硼（BP)係作成爲一種III-V族化合物半導 體（參照 Nature，179(Νο·4569)(1957)，1075 頁），至於 間接遷移型半導體之帶隙有數種値。例如，B.Stcne等 氏對堆積在石英板上之多結晶之B P膜藉光學上之吸收 法得出約6eV之室溫帶隙（參照Phys. Rev. Lett.，Vol.4, N o. 6( 1 9 60)，2 8 2〜2 84 頁）。另外，依 J.L· Peret 歸納出 559899 五、發明說明（2) BP 之帶隙約爲 6.0eV(參照 J.Am.Ceramic Soc.,47(l) ( 1 964)，第44〜46頁）。另外，N.Sclar根據離子半徑値 及共有半徑値給與絕對零度（ = 0K)之帶隙爲6.20eV(參照 J.Appl.Phys.，3 3 ( 1 0)( 1 962)第 2999〜3 002 頁）。另外，依 Manca之說，則是提示4.2eV之帶隙（參照J.Phys. Chem， Solids,20(1961)，268〜273 頁）。 另外，R.J.Archer 等氏從由磷化鎳（nickel phosphide) 融液成長之單結晶BP得出立面體BP之室溫帶隙爲 2eV(參照 phys.Rev，Lett·，12(19)(1964)，第 538 〜540 頁）。藉根據結合能量値之理論計算得出2 . 1 eV帶隙（參 照 J.Appl.Phys.，3 6( 1 96 5)，第 3 3 0〜331 頁）。磷化硼（BP) 之帶隙有上述那樣之大差異（參照J.Phys. Chem. solid， 29( 1 96 8)，第1 02 5〜1 03 2頁），及BP之帶隙約爲2eV之 情形係自來之通例（參照（1) R C A R e v i e w，2 5 ( 1 9 6 4)，第 159 〜167 頁），（2)Z.anory.allg.Chem.第 349(1967) ’ 第 151 〜157 頁，（3)上述之 J.Appl.Phys.，36(1965)。（4)上述 之「半導體裝置槪論」，及（5)參照培風館，1 994年5 月2 0日發行初版，赤崎勇編著「111 - V族化合物半導 體」，第150頁）。 磷化硼（BP)及以組成式BxAlyGau-YNkPJiK ， 〇Sy<l，O^X + Y^l，0<Z^1)記述之BP系混晶係被利用做 爲構成半導體發光元件之功能層。例如，由BP作成之 單一層（單層）用於在短波長可視發光二極體（L E D)或者 559899 五、發明說明（3) 雷射二極體（LD)上構成緩衝層以往係有其例（日本專利 申請公報特開平2-275 682號）。另外，也知曉從BP單 層和BxAlyGa^.YNuPz混晶單層之超晶格構造構成Pn 接合型之異類接合構造之發光部之例（參照日本專利申 請公報特開平1 0-2425 1 4號說明書）。另外，也有從與 BxAlyGai_x_YNi_zPz混晶單層行超晶格構造構成_壁層 之技術（參照日本專利申請公報特開平2-2 8 8 3 7 1號說明 書）。室溫時之帶隙作爲2eV之磷化硼（BP)，因不對發 光層施予障壁作用之故，上述之以往例，係利用將BP 和氮化鋁（A1N)等拌和混晶以提高室溫時之帶隙到，例 如，2.7eV之含氮混晶層（參照上述之日本專利申請公報 特開平第2-288371號）。 另外，也知悉利用BP單層以構成異類雙極性電晶 (h e t e 1· 〇 b i ρ ο 1 a r t r a η s i s t 〇 r) ( Η B T)之例（參照 J · E 1 e c t r 〇 c h e m · Soc.，1 2 5 (4)( 1 97 8 )，第 63 3 〜6 3 7 頁）。此以往之 HBT，係 使用藉乙硼烷（B2H6)/膦（PH3)系氣相成長法，在具有 (1〇〇)面之矽（Si)結晶基板上成長，帶隙爲2. OeV之BP 單層（參照上述之 J.Electro Chem· Soc.，1 25( 1 978))。另 外，也有揭示將帶隙爲2.OeV之BP單層做爲窗（window) 層以構成太陽電池（solai· cell)之技術（參照上述之J. Electrochem. Soc.，125(1978))。 如上述，以往之半導體元件係由帶隙約爲2 e V之磷化 硼（B P )或者含有該帶隙之B P之混晶構成。在以室溫之 559899 五、發明說明（4) 帶隙爲1.1 eV之Si做爲母體材料而構成之上述太陽電 池之技術上揭露出即使係爲將帶隙作成2. OeV之BP 層，即因母體爲Si之故而使帶隙變大，導致無法有效 地利用窗層（參照上述之J.Electrochem. Soc.,125 ( 1 97 8))。但是另外一方面，以Si爲基板形成BP層之以 往技術，有這樣之報告，其即依做爲基板之Si單結晶 之面方位，帶隙有被窄化之情事（參照西永頌著「應用 物理」，第45卷第9號（1976)，第891〜897頁）。另有 報告指示相較於形成在具有（100)面之Si基板上之BP 層，在具有（1 1 1)面之Si基板上者，因其面缺陷密度 大，故形成在具有（Π1)面之Si基板上之BP層逐變成不 透明（參照上述之「應用物理」，第895〜8 96頁）。另 外，有報告指示因面缺陷多之故晶格常數也變大，進而 帶隙更形狹窄（參照上述之「應用物理」，第896頁）。 晶格常數和帶隙具有關連（correlation)—事自來即已知 曉，帶隙隨著晶格常數變小而增大一事係眾所皆知（參 照上述之「ΠΙ-V族化合物半導體」，第31頁）。換言 之，據以往之硏究例，指示依形成ΒΡ層之條件，結果 ΒΡ層之帶隙變成比通用之約2eV更小之ΒΡ帶隙。因此 種低度之帶隙，導致具有無法簡便地從磷化硼（BP)結晶 層構成高耐壓之耐環境型半導體元件之缺點。 (發明欲解決之課題） 例如，室溫時之發光波長爲45 0nm(iianometer)之異類 559899 五、發明說明（5) 接合型之藍色led或LD係利用室溫，帶隙爲2.8eV之 發光層。另外，欲使障壁（clad)作用及於此發光層，須 由室溫時之帶隙至少約爲2eV以上之半導體材料構成障 壁層。是故，以往在構成磷化硼（BP)系發光元件之異.類 接合發光部之際，具有無法從室溫時之帶隙約爲2eV之 磷化硼（BP)構成障壁層之缺點。因此，以往之技術係如 上述那樣，形成含有BP之混晶，例如，形成 BxAlyGamN^Pz之多元結晶以作成帶隙高之障壁層 (參照上述日本專利申請公報特開平2-2 8 8 3 7 1號）。但 是，構成元素數多之混晶之情形，控制構成元素之組成 比等則需要高度之技術，且更不易得出良質之結晶層一 事係爲眾知者（參照上述「半導體裝置槪論」，第24 頁）。是於。以往之成膜技術具有無法簡便地形成障壁 層那類之BP系混晶層之問題點。 另外，例如，以往之npn型HBT，帶隙爲2.0eV之 BP層係被用作爲η型射極（emitter)(參照上述之J. Electrochem, Soc.，125(1978))。另一方面，P 型基極 (base)層係使用P形之Si層（參照上述之J· Electrochem Soc.，1 2 5 ( 1 97 8))。Si之帶隙約爲l.leV，因此，BP射極 層和Si基極層之異類接合構造間之帶隙之差異僅約爲 0.9eV。若因射極層和基極層之帶隙之差異作得比以往 者大之B P層構成時能更抑制從基極層流至射極層之基 極電流之洩漏，提高電流傳送率（=射極電流/集極 559899 五、發明說明（6) (collector)電流）之特性（參照上述之赤崎勇編著「III-V 族化合物半導體」，第23 9〜242頁），進而推知能得出 優良特性之HBT。 屬於閃鋅礦（Z i n c b 1 e n d e)結晶型，正確的說，屬於立 面體硫化鋅礦型（3?1^^1以）（參照飛利浦（？11丨11]3)著， 「半導體結合論」吉岡書店（公司），1 9 8 5年7月25日 發行，第3版），第14〜15頁）之磷化硼（BP)單結晶之晶 格常數係爲4.5 3 8 A(參照上述之「半導體裝置槪論」， 第28頁）。另外，有將氮（N)組成比爲0.97之立面體晶 之鱗氮化鎵（gallium nitride phosphide)混晶（組成式）Ga N 0.9 7PG. 03或者銦（In)之組成比爲0.1之氮化鎵·銦 0&0.9〇111〇.1()>^等之晶格常數作成爲4.538人之111族氮化 物半導體者。因此，若利用BP層和上述那樣之III族氮 化物半導體時則能構成，例如，顯現高電子移動性優良 之晶格匹配積層系之二維電子場效型電晶體（TEGFET)(K Seager著「半導體之物理學（下）」（參照吉岡書店（公 司）1991年6月25日發行第1版，第3 5 2〜3 5 3頁）。例 如，能將上述直接電子遷移型之III族氮化物半導體作 爲二維電子（TEG)之電子行走層，另外將間接電子移動 型之BP層作爲間隔（間隔）層或者電子供給層而構成 TEGFET。利用BP層之III族氮化物半導體TEGFET， 若係由對電子行走層作異類接合之間隔層或電子供給層 之帶隙作成比以往者大之磷化硼（BP)構成時則與電子行 559899 五、發明說明（7) 走層作異類接合之界面上之障壁差能更大。因此之故， 在異類接合之界面附近之電子行走層內之領域變成優於 畜積一維電子’進而得出顯現筒電子移動性之III族氮 化物半導體TEGFET。 若能利用室溫帶隙作得大之BP層時則也能使其與其 它半導體層之傳導帶之不連續性（d i s c ο n t i n u i t y)作得更 大。帶（band)之不連續性大，障壁差作得大之異類接合 構成能有效率地蓄積二維電子，進而有效於呈現高電子 移動性。屬於磁電轉換元件之赫爾（Hall)元件，若利用 電子移動性大之構造體時能良好地得出對磁性之靈敏度 更高之元件（參照片岡昭榮著「磁電轉換元件」（日刊工 業新聞社（公司），昭和46年2月1日發行第4版，第 5 6〜58頁）。因此，推知實現具備帶隙作得比以往者大之 BP層之異類接合構成也對構成發揮高積靈敏度（product sensitivity)(參照上述之「磁電轉換元件」，第56頁）之 高靈敏度之赫爾元件有所貢獻。 另外，以S i單結晶做爲基板之，例如，宵特基 (schottky)障壁（barrier)二極體，若能形成具有大於約 2eV之室溫帶障之BP層時則能助於構成具有高耐電壓 特性之肯特基障壁二極體。帶隙作得愈大，愈能將半導 體材料特性上之固有載體（intrinsic carrier)密度抑制得 低（參照上述之「III-V族化合物半導體」，第172〜174 頁），進而推知能良好地構成能在高溫下動作之耐環境 559899 五、發明說明（8) 元件。 如上述之以往例’利用帶隙作成約爲2 e V之B P層以 構成半導體一事係自來之通例。推知若能製出帶隙作成 更大之B P層時則能達成半導體元件特性之改善，提 昇。過去之硏究例，得知也有如上述那樣，形成具有約 6eV高之帶隙BP層之例（參照上述之phyS. Rev. Lett.， 4(6)( 1 960))。但是，這是多結晶層，對構成半導體元件 之活性層和功能層並非一定合宜。但是，帶隙若變爲這 麼大之寬廣間隙（wide gap)半導體時則不易藉摻雜 (doping)控制傳導及載體密度。適合於構成TEGFEG之 間隙層和電子供給層或者HBT之射極層等之半導體元 件之功能層係爲室溫帶隙作成約3 e V之B P結晶層。 依有關化合物半導體之帶隙之過去硏究，得知帶隙係 隨著構成元素之平均原子序號愈小而變大之傾向（參照 笛木和男他著「應用化學序列3電子材料之化學」（參 照九善（公司），昭和56年7月20曰發行），第26〜29 頁）。平均原子序號係爲構成化合物半導體之元素之原 子序號之算術平均値。第1圖係示出各種族化合 物半導體之室溫帶隙與平均原子序號之關係。例如，由 鎵（原子序號=31)和砷（原子序號=3 3)作成之砷化鎵 (0&六8)(平均原子序號=32)之室溫帶隙係爲1.436乂（參照 上述之「半導體裝置槪論」，第28頁）。這種關係in-γ 族化合物半導體亦通用，揭露具有構成原子之平均原子序號 -10- 559899 五、發明說明（9) 愈小帶隙愈大之傾向。（參照K . S e a g e 1·著「半導體之物 理學（上）」（吉岡書店（公司），1991年6月10日發行第 1版），第3 6頁）。 自平均原子序號有關之室溫帶隙之傾向能推測出離子 (ion)結合性作成比較大之III-V族化合物半導體之帶 隙。假定此傾向亦通用於構成元素間之負電性 (electronegativity)差異少，共價（covalent)結合性強之 BP結晶時則推定BP單結晶層之帶隙約爲3eV。另外， 依Van Vechten提議之「介電體法」（參照（1)J· A. Van Vechten，phys· Rev. Lett. 51 8 2( 1 96 9) » 第 891 頁）及（2) 參照赤崎勇編著「III族氮化物半導體」（培風館（公 司）’ 1 999年12月8日發行初版，第19〜21頁）），算出 B P單結晶之帶隙爲2 · 9 8 e V。此帶隙之理論計算，碳 (diam〇nd)(C)及矽（Si)之單結晶之晶格常數係分別設爲 3.567A及4.531A。另外，C(diamond)及Si之最近接原 子間之距離係分別設爲1 ·54Α及2.3 4A (參照「化學便覽 基礎編」（九善（公司），昭和45年8月20日發行，第3 版）’第1 25 9頁）。另外，計算上必要之其它値係利用提 示値（參照上述之「III族氮化物半導體」，第20〜21頁）。 目則之現狀’適合構成這樣子之半導體元件之單層尙 無揭示，室溫帶隙約爲3 e V前後之磷化硼（Β Ρ )及含有該 BP結晶之磷化硼（BP)系混晶。這是因只差形成結晶性 優良之Β P結晶層之方法尙未明確之故。亦即，在構成 -11- 559899 五、發明說明（10) ' 半導體元件之際’獲得具有適宜之帶隙之BP系混晶之 方法尙未明確。欲改善利用BP結晶層之半導體元件之 特性，須發明將帶隙作成約爲3 eV前後之BP結晶層之 形成方法。但是，不管自來即已實施利用氣相成長法等 形成BP結晶層，但是尙未揭示獲得3 eV前後之帶隙之 BP之結晶層之形成方法。本發明係以上述之以往技術 爲背景而創作出者，其目的係提供一種半導體元件和其 所需之半導體層及其製造方法，其對具備室溫時之帶隙 爲2.8電子伏特（eV)以上3.4eV以下之磷化硼（BP)層或 含有該隣化硼並以一般式ΒαΑ1βΟαγΙηι_α-β.γΡδΑ3εΝι_δ-ε (0<α<1 5〇<β<1，0<γ< 1，0<α + β + γ<ΐ , 〇<δ<1 > 0<ε<1 ^ 〇<δ + ε$1)記述之磷化硼（ΒΡ)系混晶層，這些ΒΡ層或ΒΡ 系混晶層之半導體元件，及這些BP層或BP系混晶層之 製造方法之構成予以明確化，並達成半導體元件特性之 改善及提昇。 (解決課題之措施） 亦即本發明係爲 (1) 具備由室溫時之帶隙爲2.8電子伏特（eV)以上3.4 eV 以下之磷化硼（BP)作成之半導體層之半導體元件。 (2) 如（1)項之半導體元件，其特徵爲具備由磷化硼（BP) 作成之半導體層，及該半導體層和帶隙不同之其它半導 體層之異類接合。 (3) 如（2)項之半導體元件，其特徵爲由磷化硼（BP)作 -12- 559899 五、發明說明（11) 成之半導體層和與該半導體形成異類接合之半導體層進 行晶格匹配。 (4)如（3)項之半導體元件，其特徵爲與由磷化硼（BP) 作成之半導體層形成異類接合之半導體係爲GaN〇.97 P 0 · 0 3。 (5 )(1)至（4)項任一項之半導體元件，其特徵爲由磷化 硼（BP)作成之半導體層係疊積在結晶基板上。 另外，本發明係爲 (6) 具備由含有室溫時帶隙爲2.8電子伏特（eV)以上 3.4eV以下之鱗化硼並以一般式ΒαΑ1β〇3γΙηι-α-β_γΡδ As εΝ 卜§ - ε (〇<α$ 1，0 £β<1，Ο <γ <1 j 0<α + β + γ<1 * Ο < δ <1 » 09<1，0<δ + ε$1)記述之磷化硼（ΒΡ)系混晶作成之半導 體層之半導體元件。 (7) 如（6)之半導體元件，其特徵爲磷化硼（ΒΡ)系混晶 係爲磷化鋁·硼混晶（BxAli-xPiCXXd，磷化鎵·硼（Βχ 〇&1_χΡ:0<Χ<1)-_1_，ΠΡ^$(ΒχΙη·χΡ:〇<Χ<1)。 (8) 如（6)或（7)項之半導體元件，其特徵爲具備由磷化 硼（ΒΡ)系混晶作成之半導體層，和與該半導體層者帶隙 不同之其它半導體層之異類接合。 (9) 如（8)項之半導體元件，其特徵爲由磷化硼（ΒΡ)系 混晶作成之半導體層和與該半導體層形成異類接合之半 導體層進行晶格匹配。 (1〇)(6)至（9)項中任一項之半導體元件，其特徵爲由磷 -13- 559899 五、發明說明（12) 化硼（BP)系混晶作成之半導體層係疊積在結晶基板上。 另外，本發明係爲 (Π )如（1)至（1 0)項中任一項之半導體元件，其特徵爲 具備ρ η接合構造。 (12) 如（1 1)項之半導體元件，其特徵爲其係爲發光元件。 (13) 如（1)至（10)項任一項之半導體元件，其特徵爲其 係爲受光元件。 (1 4)如（1)至（1 0)項任一項之半導體元件，其特徵爲其 係爲電晶體。 (15) 如（14)項之半導體元件，其特徵爲其係爲電場效 應型電晶體（FET)。 (16) 如（14)項之半導體元件，其特徵爲其係爲異類雙 極性電晶體（ΗΒΤ)。 (1 7)如（1)至（1 0)項中任一項之半導體元件，其特徵爲 其係爲赫爾（h a 11)元件。 另外，本發明係爲 (18) 由室溫之帶隙爲2.8電子伏特（eV)以上3.4eV以 下之磷化硼（BP)作成之半導體層。 (19) 如（18)項之半導體層，其特徵爲由磷化硼（BP)作 成之半導體層係疊積在結晶基板上。 (20) 由含有室溫時之帶隙爲2.8電子伏特（eV)以上 3.4eV以下之磷化硼（BP)並以一般式BaAlpGaYIn丨.α·ρ· γΡδΑ8εΝι.δ.ε(0<α<1,0<β<1 > 〇<γ<1 J 0<α + β + γ<1 > 0<δ<1 > -14- 559899 五、發明說明（13) 〇$ε<1，0<δ + Κΐ)記述之磷化硼（BP)系混晶作成之半導 體層。 (21) 如（20)項之半導體層，其特徵爲磷化硼（ΒΡ)系混 晶係爲磷化銘·硼混晶（Β X A11 · X Ρ : 0 < X < 1)，磷化鎵.硼混 晶（6)(0&1.>(?:0<乂<1)或磷化銦.硼（6)(1111_)^:〇<又<1)。 (22) 如（20)或（21)項之半導體層，其特徵爲由磷化硼 (Β P)系混晶作成之半導體層係疊積於結晶基板上。 另外，本發明係爲 (23) 如（18)至（22)項任一項之半導體層之成長方法， 其特徵爲藉氣相成長法成長半導體層。 (24) 如（2 3)項之半導體層之成長方法，其特徵爲係在 75 0 °C以上1 20 0 °C以下之溫度下成長半導體層。 (25) 如（23)或（24)項之半導體層成長方法，其特徵爲 氣相成長方法係爲有機金屬化學氣相沉積法（Μ 0 C V D ) 法。 (2 6)如（2 5)項之半導體層之成長方法，其特徵爲在成 長半導體層之際，含磷（Ρ)之V族元素源之合計之供給量 對含硼（Β)之III族元素源之合計之供給量之比率係爲15 以上60以下，且半導體層之成長速度係爲每分鐘20A 以上3 0 0 A以下。 另外，本發明係爲 (2 7) —種半導體層之成長方法，其係在結晶基板h， 藉MOCVD法，於25(TC以上7 5 0 °C以下之溫度下形成 -15- 559899 五、發明說明（14) 由非晶質爲主體之磷化硼（BP)或磷化硼（BP)系混晶作成 之緩衝層，然後在該緩衝層上成長由室溫時之帶隙爲 2.8電子伏特（eV)以上3.4eV以下之磷化硼（BP)作成之 半導體層。 (2 8)如（2 7)項之半導體層之成長方法，其特徵爲在結 晶基板上，藉MOCVD法，於25 0°C以上75 0°C以下之 溫度下形成由非晶質爲主體之磷化硼（BP)或磷化硼（BP) 系混晶作成之緩衝層，然後在該緩衝層上成長由含有室 溫時之帶隙爲2.8電子伏特（eV)以上3.4eV以下之磷化 硼（BP)，並以一般式 BaAlpGaYlnh-hPsAssN^-dfXaSl， 0<β<1，0<γ< 1，0<α + β + γ<1，0<δ<1，0<ε<1，0<δ + ε<1) 記述之磷化硼（ΒΡ)系混晶成成之半導體層。 (29) 如（28)項之半導體層之成長方法，其特徵爲磷化 硼（ΒΡ)系混晶係爲磷化鋁·硼混晶（BxAluPiCXXd)，磷 化鎵·硼混晶（B X G a丨_ X P : 0 < X < 1 )，或磷化銦·硼混晶 (Bxlin-X P:0<X<1)。 (30) 如（27)至（29)項任一項之半導體層之成長方法， 其特徵爲藉氣相成長法在7 5 0 °C以上1 200 °C以下之溫度 下成長半導體層。 (31) 如（27)至（30)至任一項之半導體層之成長方法， 其特徵爲藉MOCVD法成長半導體層。 (發明之實施形態） 具備由本發明之磷化硼（BP)或磷化硼（BP)系混晶作成 -1 6 - 559899 五、發明說明（15) 之半導體層之半導體兀件能以，例如，砂（Silicon)，鱗 化鎵（GaP)，砷化鎵（GaAs)等之半導體單結晶做基板而 構成。例如，LED或LD或受光元件，若使用具有導電 性之這些半導體單結晶做爲基板時則因能簡單地配置電 極而具有能簡便地將元件構成爲發光及受光元件之優 點。相較於ιπ-ν族化合物半導體，融點高之矽（Si單結 晶），具有耐於1 000°C前後之高溫下進行晶膜（expitaxial) 成長之耐熱性，因此能良好地被利用做爲基板。另外， 在進行積體各種元件之際也能良好地被用做爲基板。藍 寶石（saPphire)(a-Al203單結晶）等之氧化物單結晶藉其 之電氣絕緣性，發揮，例如，防止元件動作電流之洩漏 之作用。因此之故，例如，能良好地應用於抑制洩極 (drain)電流之洩漏量之電場效果型電晶體（FET)。另 外，鑽石（diamond)或碳化矽（SiC)熱傳導率比較高，因 此，特別適宜做爲元件冷卻所需之電力（power)用FET 等之基板。 做爲基板，良好之表面之面方位係爲{ 1 〇〇 }、{ 1 1 〇 }， 或者{Π 1}等之低次之密拉（miller)指數面。藉從這些低 密拉指數面成數度到數十度之角度之範圍傾斜之面做爲 表面之Si單結晶也能被利用做爲基板。Si，GaP，或 GaAs等之閃鋅礦（Zinc-blende)型結晶{ 1 1 1 }結晶面相較 於U 〇 〇 }結晶面，構成結晶之原子較爲稠密。因此之 故，有效地抑制構成晶膜成長層之原子擴散，侵入基 -17- 559899 五、發明說明（16) 板內。具有{ 3 Π }和{ 5 11 }等之高次之密拉指數面之單結 晶具有抑制成長層構成元素侵入如通道作用（channeling) (參照 R.G.WILSON 及 G.R.BREWER 著，，ION BEAMS With Application to Ion Implantation5,(John Wiley & Sons Inc·，1 973 )，第263〜26 5頁）那樣之單結晶基板之內 部。但是，反映基板表面之面方位，上層之晶膜成長層 之成長方法也變成高次，導致產生裁斷各個元件之流程 變成複雜等不良之情形。 具備由本發明之磷化硼（BP)作成之半導體層之半導體 元件之特徵係具備特定範圍之帶隙之磷化硼（BP)半導體 層。另外，具備由本發明之磷化硼（BP)系混晶作成之半 導體層之半導體元件之特徵係具備含有以特定帶隙之 BP構成之BP系混晶。BP系混晶係爲含有以硼（B)和磷 (P)做爲構成元素之III-V族化合物半導體混晶。例如， 係爲以一般式 BuAlpGaYlni-a-piPsAseNj.s-dO'aSl, 〇<β< 1，0<γ< 1，0<α + β + γ<1，0<δ< 1，〇<ε< 1，0<δ + ε<1 ) 曰己述之混晶。更具體g之’係爲鱗化銘·棚（Β χ A11 - χ Ρ : 0 S X S 1 )， 磷化鎵·硼（BxGa^xPWSXSl)，及磷化銦·硼（Bxlrih PiO^XSl)之混晶。另外，磷氮化硼（BPyNuCKYSI)及磷 砷化硼（BPYASl_Y:0<Y^l)或磷砷化硼·鎵(BxGauPyAsniXXSl) 等亦能爲例。 磷化硼（BP)或BP系混晶層之機械或電氣規範係依元 件而適宜地選擇。具備η形電子行走層之η通道形V. Description of the invention (1) Detailed description: (Technical field to which the invention belongs) The present invention relates to boron phosphide (BP) with a band gap at room temperature of 2.8 electron volts (eV) and 3.4 eV or less. Layer or contains boron phosphide and uses the general formula BaAlpGaYIm-a_Bu YPsAseNm (〇 < 〇 ^ l, 〇M < l, 〇 $ γ < 1,0 < α + β + γ $ 1,0 < δ $ 1,0 $ ε < 1,0 < δ + ε $ 1) The boron phosphide (BP) -based mixed crystal layer described above, a semiconductor device including these BP layers or BP-based mixed crystal layers, and the BP layer or BP-based mixed crystal layer Production method. (Prior art) Group III-V compound semiconductors made of boron (B) and group V elements of the periodic table include boron nitride (BN), boron phosphide (BP), and boron arsenide (BAs) . For example, hexahedral crystal boron nitride (BN) is an indirect migration semiconductor with a band gap of 7.5 electron volts (eV) at room temperature (see (Peifeng Hall (Company), March 1995) The first edition of the invention was published on the 30th. Teramoto wrote "Semiconductor Device Theory" on page 28.) Boron arsenide (BAs) is a well-known in-v group compound with indirect migration at a band gap of about 0.85 eV at room temperature. (Refer to "Semiconductor Device Theory" above.) In addition, boron phosphide (BP) is a type III-V compound semiconductor (see Nature, 179 (No. 4569) (1957), p. 1075), and indirect There are several types of band gaps in migrating semiconductors. For example, B. Stcne et al. Obtained a room temperature band gap of approximately 6 eV by optical absorption method on a polycrystalline BP film deposited on a quartz plate (see Phys. Rev. Lett ., Vol.4, No. 6 (1 9 60), 2 8 2 ~ 2 84). In addition, according to JL · Peret, it is summarized as 559899 5. Description of the invention (2) The band gap of BP is about 6.0eV ( (See J. Am. Ceramic Soc., 47 (l) (1 964), pp. 44 ~ 46). In addition, N.Sclar provides absolute ions based on ion radius 値 and common radius 値. The band gap of zero degree (= 0K) is 6.20eV (refer to J.Appl.Phys., 3 3 (1 0) (1 962) pages 2999 ~ 3 002). In addition, according to Manca, it is 4.2eV. Band gap (refer to J. Phys. Chem, Solids, 20 (1961), pages 268 to 273). In addition, RJArcher et al. Obtained the facade from a single crystal BP grown from a nickel phosphide melt. The room temperature band gap of bulk BP is 2 eV (see phys. Rev, Lett ·, 12 (19) (1964), pages 538 to 540). The band gap of 2.1 eV is calculated based on the theory of combined energy 値 (see J.Appl.Phys., 36 (1962 5), pp. 3-30 to 331). The band gap of boron phosphide (BP) has such large differences as described above (see J. Phys. Chem. Solid, 29 (1 96 8), page 1 02 5 ~ 1 03 2), and the case where the band gap of BP is about 2eV is a common case (refer to (1) RCAR eview, 2 5 (1 9 6 4), 159 to 167), (2) Z. anory.allg. Chem. 349 (1967), pp. 151 to 157, (3) J. Appl. Phys., 36 (1965). (4) The "Semiconductor Device Theory" mentioned above, and (5) With reference to the Peifeng Museum, the first edition was issued on May 20, 1994, and Akasaki edited "111-V compound semiconductors", p. 150). Boron phosphide (BP) and the BP-based mixed crystal system described by the composition formula BxAlyGau-YNkPJiK, 〇Sy < l, O ^ X + Y ^ l, 0 < Z ^ 1) are used as a function of constituting a semiconductor light-emitting element Floor. For example, a single layer (single layer) made of BP is used to form a buffer layer on a short-wavelength visible light-emitting diode (LED) or 559899. 5. Description of the invention (3) A laser diode (LD) has a buffer layer in the past. Example (Japanese Patent Application Laid-Open No. 2-275 682). In addition, an example of a light-emitting portion of a Pn junction type heterojunction structure formed from a superlattice structure of a BP monolayer and a BxAlyGa ^ .YNuPz mixed crystal monolayer is also known (see Japanese Patent Application Laid-Open No. 0-2425 1 No. 4 Instructions). In addition, there is also a technique for constructing a wall layer from a single-layer row superlattice structure mixed with BxAlyGai_x_YNi_zPz (refer to Japanese Patent Application Publication No. Hei 2-2 8 8 3 7 1). The band gap at room temperature is 2eV of boron phosphide (BP), and because the barrier layer is not provided to the light-emitting layer, the above-mentioned conventional example uses a mixed crystal of BP and aluminum nitride (A1N) to improve the room. The temperature band gap is, for example, a nitrogen-containing mixed crystal layer of 2.7 eV (refer to the aforementioned Japanese Patent Application Publication No. Hei 2-288371). In addition, an example of using a BP single layer to constitute a heterobipolar transistor (hete 1 · 〇bi ρ ο 1 artra η sist 〇r) (Η BT) is also known (see J · E 1 ectr 〇chem · Soc., 1 2 5 (4) (1 97 8), pages 63 3 to 6 3 7). OeV 的 This conventional HBT is grown by using a diborane (B2H6) / phosphine (PH3) based vapor phase growth method on a silicon (Si) crystal substrate having a (100) plane. BP single layer (refer to J. Electro Chem. Soc., 1 25 (1 978) above). In addition, there is also disclosed a technique for forming a solar cell (solai · cell) by using a BP single layer having a band gap of 2. OeV as a window layer (refer to the aforementioned J. Electrochem. Soc., 125 (1978)). As described above, a conventional semiconductor device is composed of boron phosphide (B P) having a band gap of about 2 e V or a mixed crystal of B P containing the band gap. OeV's BP layer, which is technically disclosed in the above-mentioned solar cells constructed with Si at room temperature of 559899 V. Description of the invention (4) Band gap of 1.1 eV as the parent material The band gap is enlarged because the precursor is Si, which makes it impossible to effectively use the window layer (refer to the aforementioned J. Electrochem. Soc., 125 (1 97 8)). However, on the other hand, in the conventional technology of forming a BP layer using Si as a substrate, there are reports that the band gap is narrowed according to the plane orientation of the Si single crystal of the substrate (refer to Xiyong Song "Application Physics ", Vol. 45 No. 9 (1976), pp. 891 ~ 897). Another report indicates that, compared with a BP layer formed on a Si substrate having a (100) plane, a Si substrate having a (1 1 1) plane has a higher surface defect density and is therefore formed on a substrate having a (Π1) The BP layer on the surface Si substrate gradually becomes opaque (see "Applied Physics" above, pp. 895-8896). In addition, there are reports indicating that the lattice constant becomes larger due to the large number of surface defects and the band gap becomes narrower (see “Applied Physics” above, p. 896). There is a correlation between the lattice constant and the band gap-it has been known since nature that it is well known that the band gap increases as the lattice constant becomes smaller (refer to the above-mentioned "III-V compound semiconductor", Page 31). In other words, according to the previous research examples, it is instructed that, depending on the conditions for forming the BP layer, the band gap of the BP layer becomes a BP band gap smaller than the general 2eV band gap. Therefore, such a low band gap has the disadvantage that it is not easy to construct an environment-resistant semiconductor device with a high withstand voltage from a boron phosphide (BP) crystal layer. (Problems to be Solved by the Invention) For example, the luminous wavelength at room temperature is 45 0nm (iianometer) and other 559899. 5. Description of the invention (5) The bonding type blue LED or LD uses room temperature with a band gap of 2.8eV. Luminescent layer. In addition, in order for the clad to act on this light-emitting layer, the barrier layer must be made of a semiconductor material with a band gap of at least about 2 eV or more at room temperature. For this reason, conventionally, in the formation of boron phosphide (BP) -based light-emitting devices, there has been a disadvantage that boron phosphide (BP), which has a band gap of about 2 eV at room temperature, cannot form a barrier layer when bonding light-emitting parts. Therefore, the conventional technique is to form a mixed crystal containing BP as described above, for example, to form a multiple crystal of BxAlyGamN ^ Pz to form a barrier layer with a high band gap (see Japanese Patent Application Laid-Open No. 2-2 8 8 3 7 number 1). However, in the case of mixed crystals with a large number of constituent elements, controlling the composition ratio of the constituent elements requires a high degree of technology, and it is more difficult to obtain a good crystalline layer (refer to the above-mentioned "semiconductor device theory", Page 24). Yes. The conventional film formation technology has a problem that a BP-based mixed crystal layer such as a barrier layer cannot be easily formed. In addition, for example, in the conventional npn-type HBT, a BP layer system with a band gap of 2.0 eV is used as an n-type emitter (see J. Electrochem, Soc., 125 (1978) described above). On the other hand, a P-type base layer is a P-shaped Si layer (refer to J. Electrochem Soc., 1 2 5 (1 97 8)). The band gap of Si is about l.leV. Therefore, the difference in the band gap between the heterojunction junction structure of the BP emitter layer and the Si base layer is only about 0.9 eV. If the structure of the BP layer is larger than the former due to the difference in the band gap between the emitter layer and the base layer, the leakage of the base current flowing from the base layer to the emitter layer can be more suppressed, and the current transfer rate (= Emitter current / collector 559899 5. The characteristics of the invention (6) (collector) current (refer to the above-mentioned "III-V compound semiconductor" edited by Yu Akasaki, p. 23 9 ~ 242), and it can be inferred that HBT with excellent characteristics. It belongs to the crystal type of Zincb 1 ende. To be more precise, it belongs to the cubic zinc sulfide type (3? 1 ^^ 1) (refer to Philips (? 11 丨 11) 3). On "Yoshioka Bookstore (Company), July 25, 1965, 3rd Edition), pages 14 ~ 15) The lattice constant of boron phosphide (BP) single crystal is 4.5 3 8 A ( (See "Semiconductor Device Theory" above, page 28). In addition, there is a gallium nitride phosphide mixed crystal (compositional formula) having a composition ratio of nitrogen (N) of 0.97, and the composition ratio of Ga N 0.9 7PG. 03 or indium (In) is 0.1. The lattice constants of gallium nitride, indium & 0.900110.1 () > ^ etc. are made as a Group 111 nitride semiconductor of 4.538 people. Therefore, if a BP layer and a group III nitride semiconductor as described above are used, it can be constructed, for example, a two-dimensional electronic field-effect transistor (TEGFET) (K Seager, which exhibits a lattice-matched multilayer system with excellent high electron mobility). "Physics of Semiconductors (Part 2)" (refer to Yoshioka Bookstore (Company), 1st edition, June 25, 1991, pages 3 5 2 to 3 5 3). For example, the above-mentioned direct electron transfer type III A nitride semiconductor is used as a two-dimensional electron (TEG) electron walking layer, and an indirect electron-moving BP layer is used as a spacer (spacer) layer or an electron supply layer to form a TEGFET. A group III nitride semiconductor TEGFET using the BP layer, if When it is composed of a gap layer that heterogeneously bonds the electron walking layer or a band gap of the electron supply layer, which is made of boron phosphide (BP) that is larger than the previous one, it is connected to the electronic line 559899. 5. Description of the invention (7) The heterogeneous bonding of the walking layer The barrier difference at the interface can be greater. Therefore, the field in the electron walking layer near the heterojunction interface becomes better than the one-dimensional electron of the product, and a group III nitride showing the electron mobility of the tube is obtained. Semiconductor TEGFET. If the BP layer with a large room temperature band gap can be used, the discontinuity of the conduction band between it and other semiconductor layers can be made larger. The discontinuity of the band Large heterogeneous junctions with large barriers can efficiently accumulate two-dimensional electrons, which is effective in showing high electron mobility. Hall elements, which are magnetoelectric conversion elements, use structures with large electron mobility. A device with higher sensitivity to magnetism can be obtained in good time (see photo "Osaka Sakae's" Magnetoelectric Conversion Device "(Nikkan Kogyo Shimbun (Company), 4th edition, February 1st, Showa 46, Issue 5 6 ~ (Page 58). Therefore, it is inferred that the realization of a heterogeneous junction structure having a BP layer having a band gap larger than that of the conventional one also exerts high product sensitivity on the structure (refer to the above-mentioned "Magnetoelectric Conversion Element", page 56). A high-sensitivity Hull element contributes. In addition, using Si single crystal as a substrate, for example, a Schottky barrier diode, if it can form a room temperature band greater than about 2eV The barrier BP layer can help to form a Kentky barrier barrier diode with high withstand voltage characteristics. The larger the band gap is, the lower the intrinsic carrier density in the characteristics of semiconductor materials can be suppressed (see The above-mentioned "Group III-V compound semiconductor", pp. 172 to 174), and it is further inferred that an environment-resistant 559899 capable of operating at high temperatures can be well formed. 5. Description of the invention (8) The device. It is a common practice for the gap to form a BP layer of about 2 e V to constitute a semiconductor. It is inferred that if the band gap can be made to form a larger B P layer, the characteristics of the semiconductor device can be improved and improved. In the past research examples, it was found that there is also an example in which a band gap BP layer having a height of about 6 eV is formed as described above (refer to the aforementioned phyS. Rev. Lett., 4 (6) (1 960)). However, this is a polycrystalline layer, which is not necessarily suitable for the active layer and the functional layer constituting a semiconductor device. However, if the band gap becomes such a wide wide gap semiconductor, it is difficult to control doping and carrier density by doping. The functional layer suitable for semiconductor elements such as the gap layer and electron supply layer of TEGFEG or the emitter layer of HBT is a B P crystal layer with a band gap of about 3 e V at room temperature. Based on the past research on the band gap of compound semiconductors, we know that the band gap tends to become larger as the average atomic number of the constituent elements is smaller (refer to "Fujigi and Otoko" Applied Chemistry Sequence 3 Electronic Material Chemistry "(see Jiushan (Company), July 20, Showa 56), pages 26 ~ 29). The average atomic number is the arithmetic mean of the atomic numbers of the elements constituting the compound semiconductor. Fig. 1 is a graph showing the relationship between the room temperature band gap and the average atomic number of various compound semiconductors. For example, the room temperature band gap of gallium arsenide (0 & 6: 8) (average atomic number = 32) made of gallium (atomic number = 31) and arsenic (atomic number = 3 3) is 1.436 乂 (refer to the above " On Semiconductor Devices ", page 28). This relationship is also common for in-γ group compound semiconductors, and it has been revealed that the average atomic number of constituent atoms is -10- 559899 5. Explanation of the invention (9) The smaller the band gap, the larger the tendency. (Refer to K. S e a g e 1, "Physics of Semiconductors (Part 1)" (Yoshioka Bookstore (Company), 1st edition, June 10, 1991), p. 36). From the tendency of the room temperature band gap related to the average atomic number, it can be inferred that the ion-binding property makes a relatively large band gap of a III-V compound semiconductor. It is assumed that this tendency is also commonly applied to constituent elements that have a small difference in electronegativity. When covalently bonded BP is crystallized, the band gap of the BP single crystal layer is estimated to be about 3 eV. In addition, according to the "Dielectric Method" proposed by Van Vechten (see (1) J. A. Van Vechten, phys. Rev. Lett. 51 8 2 (1 96 9) »page 891) and (2) refer to Akasaki Yong edited "Group III nitride semiconductor" (Peifeng Pavilion (Company) 's first edition, December 8, 999, pages 19 ~ 21)), and calculated the band gap of BP single crystal as 2.98 eV. The theoretical calculation of this band gap, the lattice constants of single crystals of carbon (diam) (C) and silicon (Si) are set to 3.567A and 4.531A, respectively. In addition, the distances between the nearest atoms of C (diamond) and Si are set to 1.54A and 2.3 4A, respectively (refer to "Basic Chemistry Guidebook" (Nine Goods (Company), issued on August 20, Showa 45, No. 3rd Edition) 'p. 1 25 9). In addition, other calculations that are necessary for calculation are the use indications (see "Group III nitride semiconductors" above, pages 20 to 21). The current status of the project 'is suitable for the formation of a single layer of such a semiconductor device. It has not been revealed that the room temperature band gap is about 3 e V of boron phosphide (B P) and the boron phosphide (BP) containing the BP crystal. crystal. This is because the method for forming a β P crystal layer with excellent crystallinity is not clear. That is, the method of obtaining a BP-based mixed crystal with a suitable band gap when constructing -11- 559899 V. Invention Description (10) 'Semiconductor Element' is not clear. In order to improve the characteristics of a semiconductor device using a BP crystal layer, it is necessary to invent a method for forming a BP crystal layer with a band gap of about 3 eV. However, the formation of a BP crystal layer by a vapor phase growth method or the like has been carried out regardless of its origin, but a method of forming a BP crystal layer having a band gap around 3 eV is not disclosed. The present invention was created with the background of the above-mentioned prior art. The object of the present invention is to provide a semiconductor element, a semiconductor layer required for the semiconductor element, and a method for manufacturing the same. The boron phosphide (BP) layer above 3.4eV or below contains the adjacent boron phosphide and has the general formula BαΑ1βΟαγΙηι_α-β. ; α + β + γ < ΐ, 〇 < δ < 1 > 0 < ε < 1 ^ 〇 < δ + ε $ 1) The boron phosphide (BP) -based mixed crystal layer described in these, these PB layers or PB-based The composition of the semiconductor device of the mixed crystal layer and the manufacturing method of these BP layers or BP-based mixed crystal layers are clarified, and the characteristics of the semiconductor device are improved and improved. (Measures to Solve the Problem) That is, the present invention is a semiconductor device having a semiconductor layer made of boron phosphide (BP) with a band gap at room temperature of 2.8 electron volts (eV) or more and 3.4 eV or less. (2) The semiconductor device according to item (1) is characterized by having a semiconductor layer made of boron phosphide (BP), and a heterojunction between the semiconductor layer and another semiconductor layer having a different band gap. (3) The semiconductor device according to item (2) is characterized in that boron phosphide (BP) is used as -12-559899. 5. Description of the invention (11) The semiconductor layer formed and the semiconductor layer forming a heterojunction with the semiconductor are crystallized. Grid match. (4) The semiconductor device according to item (3), wherein the semiconductor system forming a heterojunction with a semiconductor layer made of boron phosphide (BP) is GaN 0.97 P 0 · 03. (5) The semiconductor device according to any one of (1) to (4), characterized in that a semiconductor layer made of boron phosphide (BP) is stacked on a crystalline substrate. In addition, the present invention is (6) including a scaled boron containing a band gap of 2.8 electron volts (eV) or more and 3.4 eV or less at room temperature and a general formula BαΑ1β〇3γΙηι-α-β_γΡδ As ε Ν Β-ε ( 〇 < α $ 1,0 £ β < 1, 〇 < γ < 1 j 0 < α + β + γ < 1 * Ο < δ < 1 »09 < 1,0 < δ + ε $ 1) The described boron phosphide (BP) is a semiconductor element of a semiconductor layer made of mixed crystals. (7) The semiconductor device according to (6), characterized in that the boron phosphide (BP) -based mixed crystal system is aluminum phosphide-boron mixed crystal (BxAli-xPiCXXd, gallium phosphide-boron (Βχ 〇 & 1_χΡ: 0 & lt X < 1) -_ 1_, ΠP ^ $ (ΒχΙη · χP: 〇 < X < 1). (8) A semiconductor device such as (6) or (7), which is characterized by having boron phosphide (ΒΡ A semiconductor layer made of a mixed crystal is heterogeneously bonded to another semiconductor layer having a band gap different from that of the semiconductor layer. (9) The semiconductor element according to item (8) is characterized by being boron phosphide (BP) mixed. A crystal-made semiconductor layer and a semiconductor layer forming a heterojunction with the semiconductor layer are lattice-matched. The semiconductor element according to any one of (10) to (6) to (9), characterized in that it is composed of phosphorus-13-559899 5. Description of the invention (12) A semiconductor layer made of boron compound (BP) -based mixed crystals is stacked on a crystalline substrate. In addition, the present invention is (Π) such as any one of (1) to (10) The semiconductor element is characterized by having a ρ η junction structure. (12) The semiconductor element such as (1 1) is characterized in that it is a light emitting element. (13) As in any one of (1) to (10) The semiconductor element is characterized by being a light-receiving element. (1 4) The semiconductor element according to any one of (1) to (10) is characterized by being a transistor. (15) Such as (14) The semiconductor element of the item is characterized as being an electric field effect transistor (FET). (16) The semiconductor element of item (14) is characterized as being a heterobipolar transistor (ΗΒΤ). (1 7 ) The semiconductor device according to any one of (1) to (10), characterized in that it is a haar (ha 11) device. In addition, the present invention is (18) a band gap from room temperature is 2.8 A semiconductor layer made of boron phosphide (BP) with an electron volt (eV) and 3.4 eV or less. (19) The semiconductor layer according to item (18) is characterized in that the semiconductor layer system made of boron phosphide (BP) is stacked. On a crystalline substrate: (20) It contains boron phosphide (BP) with a band gap of 2.8 electron volts (eV) or more and 3.4 eV or less at room temperature and the general formula BaAlpGaYIn 丨 .α · ρ · γρδΑ8εΝι.δ.ε (0 < α < 1,0 < β < 1 > 〇 < γ < 1 J 0 < α + β + γ < 1 > 0 < δ < 1 > -14- 559899 5. Description of the invention (13) 〇 $ ε < 1,0 < δ + Κΐ) The semiconductor layer made of boron phosphide (BP) based mixed crystals. (21) The semiconductor layer according to item (20), characterized in that boron phosphide (BP) based mixed crystals are phosphating Ming boron mixed crystal (B X A11 · X Ρ: 0 < X < 1), gallium phosphide. Boron mixed crystal (6) (0 & 1. > (?: 0 < 乂 < 1) or Indium phosphide. Boron (6) (1111 _) ^: 〇 < 1). (22) The semiconductor layer according to item (20) or (21), characterized in that a semiconductor layer made of boron phosphide (B P) -based mixed crystals is stacked on a crystalline substrate. In addition, the present invention is a method for growing a semiconductor layer according to any one of (23) to (18) to (22), characterized in that the semiconductor layer is grown by a vapor phase growth method. (24) The method for growing a semiconductor layer as described in (2 3), characterized in that the semiconductor layer is grown at a temperature of 75 ° C to 120 ° C. (25) The method for growing a semiconductor layer according to item (23) or (24), characterized in that the vapor phase growth method is an organometallic chemical vapor deposition (M 0 C V D) method. (2 6) The method for growing a semiconductor layer according to item (2 5), characterized in that, when the semiconductor layer is grown, the total supply amount of the group V source containing phosphorus (P) to the III containing boron (B) The ratio of the total supply amount of the group element source is 15 or more and 60 or less, and the growth rate of the semiconductor layer is 20 or more and 300 A or less per minute. In addition, the present invention is (2 7)-a method for growing a semiconductor layer, which is formed on a crystalline substrate h by a MOCVD method at a temperature of 25 (TC above 7 5 0 ° C) -15- 559899 Description of the Invention (14) A buffer layer made of amorphous boron phosphide (BP) or boron phosphide (BP) -based mixed crystals, and then grown on the buffer layer, with a band gap of 2.8 electrons at room temperature A semiconductor layer made of boron phosphide (BP) above volts (eV) and below 3.4 eV. (2 8) The method for growing a semiconductor layer such as (2 7) is characterized in that it is performed on a crystalline substrate by the MOCVD method. A buffer layer made of amorphous boron phosphide (BP) or boron phosphide (BP) -based mixed crystals is formed at a temperature between 25 ° C and 75 ° C, and then grown on the buffer layer. Contains boron phosphide (BP) with a band gap of 2.8 electron volts (eV) and 3.4 eV or less at room temperature, and the general formula BaAlpGaYlnh-hPsAssN ^ -dfXaSl, 0 < β < 1,0 < γ < 1,0 & lt α + β + γ < 1,0 < δ < 1,0 < ε < 1,0 < 1,0 < δ + ε < 1) The semiconductor layer formed by the boron phosphide (BP) described in the above description is a mixed crystal. (29) The method for growing a semiconductor layer according to item (28), characterized in that the boron phosphide (BP) -based mixed crystal system is aluminum phosphide-boron mixed crystal (BxAluPiCXXd), and the gallium phosphide-boron mixed crystal (BXG a丨 _ XP: 0 < X < 1), or indium phosphide · boron mixed crystal (Bxlin-X P: 0 < X < 1). (30) The method for growing a semiconductor layer according to any one of items (27) to (29), characterized in that the semiconductor layer is grown by a vapor phase growth method at a temperature of 750 ° C to 1200 ° C. (31) The method for growing a semiconductor layer according to any one of (27) to (30) to, characterized in that the semiconductor layer is grown by a MOCVD method. (Embodiment of the Invention) A semiconductor element provided with a semiconductor layer of boron phosphide (BP) or boron phosphide (BP) -based mixed crystal according to the present invention may be 1-6-559899. 5. The semiconductor element of the semiconductor layer described in (15) may be, for example, , Semiconductor (Silicon), scaled gallium (GaP), gallium arsenide (GaAs), and other semiconductor single crystals as substrate. For example, when LEDs or LDs or light-receiving elements are used as substrates, these semiconductor single crystals having conductivity have the advantage that they can be easily configured as light-emitting and light-receiving elements because the electrodes can be easily arranged. Compared with ιπ-ν group compound semiconductors, silicon with a high melting point (Si single crystal) has heat resistance that can withstand the growth of the epitaxial film at high temperatures around 1 000 ° C, so it can be used well Is the substrate. In addition, it can be used well as a substrate when integrating various elements. Oxide single crystals, such as sapphire (saPphire) (a-Al203 single crystal), use their electrical insulation properties to exert, for example, the function of preventing leakage of the operating current of the device. For this reason, for example, it can be well applied to an electric field effect type transistor (FET) that suppresses the amount of leakage of a drain current. In addition, diamond or silicon carbide (SiC) has a relatively high thermal conductivity. Therefore, it is particularly suitable as a substrate for power FETs and the like required for device cooling. As a substrate, the good surface orientation is a low-order miller index surface such as {1 00}, {1 1 〇}, or {Π 1}. By using these low-density exponential surfaces as angles ranging from several degrees to several tens degrees as the surface, single Si crystals can be used as substrates. Zinc-blende-type crystals such as Si, GaP, or GaAs have {1 1 1} crystal planes, which are denser than the U ○} crystal planes. Therefore, the atomic diffusion constituting the growth layer of the crystal film can be effectively inhibited from intruding into the substrate -17- 559899 5. Description of the invention (16) The plate. Single crystals with high-order Mild index surfaces such as {3 Π} and {5 11} can inhibit the invasion of constituent elements of the growth layer such as channeling (see RGWILSON and GRBREWER, ION BEAMS With Application to Ion Implantation 5, (John Wiley & Sons Inc., 1 973), pages 263 to 265, inside a single crystal substrate. However, reflecting the orientation of the surface of the substrate, the growth method of the upper crystal film growth layer has also become high-order, leading to problems such as the complexity of the process of cutting individual components. A feature of a semiconductor device having a semiconductor layer made of boron phosphide (BP) of the present invention is a boron phosphide (BP) semiconductor layer having a band gap in a specific range. A semiconductor device including a semiconductor layer made of a boron phosphide (BP) -based mixed crystal of the present invention is characterized by having a BP-based mixed crystal including a BP having a specific band gap. The BP-based mixed crystal system is a group III-V compound semiconductor mixed crystal containing boron (B) and phosphorus (P) as constituent elements. For example, the system is the general formula BuAlpGaYlni-a-piPsAseNj.s-dO'aSl, 〇 < β < 1,0 < γ < 1,0 < α + β + γ < 1,0 < δ < 1, 〇 < ε < 1,0 < δ + ε < 1) is a mixed crystal already described. More specifically, the system is a mixture of scaly inscriptions and sheds (B χ A11-χ P: 0 SXS 1), gallium phosphide and boron (BxGa ^ xPWSXSl), and indium phosphide and boron (Bxlrih PiO ^ XSl). crystal. In addition, boron phosphorus nitride (BPyNuCKYSI) and phosphorus boron arsenide (BPYASl_Y: 0 < Y ^ l) or boron phosphorus arsenide · gallium (BxGauPyAsniXXSl) can also be exemplified. The mechanical or electrical specifications of boron phosphide (BP) or BP-based mixed crystal layer are appropriately selected depending on the components. N-channel shape with n-shaped electron walking layer
-18- 559899 五、發明說明（17) TEGFET之電子供給層，例如，係利用層厚約1〇nm至 約5 n m，載體濃體約1 X 1 〇 18 cm -3〜約5 X 1 〇 18 cm - 3之η形 ΒΡ層等。發光二極體（LED)，用於有效率地將發光引出 外部之窗（window)層係由對應護面層等之基底層之傳導 形，屬於η形或p形，超過，例如，約1 x丨〇 18 cm - 3之 良導電性之B P或B P系混晶層所構成。另外，雷射二極 體（LD)，電流狹竅層係由與上部護面層等之基底層係爲 傳導形者相反之導電層，或著高電阻之BP或BP系混晶 層所構成。磷化硼（BP)二維半導體係爲間接（indirect) 遷移型半導體（參照上述「半導體裝置槪論」，第28 頁）。相反地，BP之飛利浦（Philips)離子結合性係小到 〇.〇〇6(參照上述「半導體結合論」，第49〜51頁）。因 此，雜質（dopant)之電氣活化率高，進而容易得出屬於 高載體濃度之低電阻之BP結晶層。本發明係良好地利 用這樣之低電阻BP層，例如，LED之電流擴散層以及 LD或FET之歐姆接觸（ohmic contact)層而構成BP系半 導體元件。另外，需要導電性之緩衝層之BP系半導體 元件，這種低電阻之BP層能良好地被利用於構成導電 性緩衝層。 本發明有關之BP結晶層及BP系混晶層係利用，例 如，眾知之有機金屬化學氣相沉積（MOCVD)法（參照 Inst. Phys. Conf. Ser.? N ο . 1 2 9 (IΟ P 5 P u b 1 i s h i n g Ltd., 1 9 93)，第157〜162)頁，分子線晶膜（MB E)法（參照 -19- 559899 五、發明說明（18) J.Solid State Chem 133(1997)，第 269〜272 頁），鹵化物 (halide)法或氫化物（hydride)法等之氣相成長法而成 長。有機金屬氣相沉積法係爲將硼（B)之有機化合物做 爲硼（B)源之氣相成長法。MOCVD法，例如，磷化硼·鎵 (BxGai_xP:0$X$l)混晶係利用由二乙基砸（（C2D3B)， 三甲基鎵（（CH3)3Ga)，或者三乙基鎵（（C2H5)3Ga)，膦 (PH3)或者三羥基（Ui alkyl)磷等之有機化合物所構成之 原料系而成長。藉鹵化物（Halide)進行之磷化硼（BP)之 結晶層之氣相成長，能利用，例如，三氯化硼（BC13)等 之硼（B)之鹵化物做爲硼（B)源，另外，三氯化磷（PC13) 等之磷之鹵化物做爲磷（P)源（參照「日本結晶成長學會 誌」），Vo 1.24，Νο· 2( 1 997)，第150頁）。另外，也有使用 三氯化硼（BC13)做爲硼（Β)源之鹵化物法（參照Appl ?1”5.，42( 1 )( 1 97 1 )，第 420〜424 頁）。氫化物（1^(11心(1)法 係爲’例如’利用硼烷（BH3)或者乙硼烷（B2H6)等之硼氫 化合物做爲硼（B)源，利用膦（PH3)等磷氫化合物做爲磷 (P)源而能成長BP結晶層。（參照（1)J. Crystal Growth， 24/25(1974)，第 193 〜196 頁，及（2)J. Crystal Growth， 1 3 2( 1 9 93 )，第 611〜613 頁）。 依氣相成長法，例如，相較於以往由鎳（Ni)-磷（P)融 液或銅（Cu)-磷（P)融液培育磷化硼（BP)結晶之所謂液相 成長方法（參照 J · E 1 e c 11. 〇 c h e m . S 〇 c ., 1 2 0 (6 ) ( 1 9 7 3 )，第 8 0 2〜8 0 6頁）’具有簡便且容易地控制β P系混晶層之層 -20- 559899 五、發明說明（19) 厚和混晶組成比之優點。另外，依氣相成長法，也具有 BP層或BP系混晶層能簡便地和其他之半導體結晶層形 成異類接合構造體之優點。特別是依具備能瞬時地變更 供給生長反應爐之氣體原料種之配管系之MOCVD方 法，能急速地改變結晶層之組成。藉異類（Hetero)接合 界面以急速改變組成之所謂抖峭之異類接合界面構造， 能有效率地蓄積低維電子。因此，自與藉MOCVD法形 成之B P層或B P系混晶層進行抖峭之異類接合界面構 造，具有，例如，實現電子移動度佳之TEGFET等之 B F系半導體元件之效果。 生長BP層或BP混晶層所需之溫度係視氣相成長方 式及做爲基板之結晶材料以及目的物之BP層或BP系混 晶層之結晶形態而定。欲得出單結晶之BP層，幾乎與 上述之一些氣相成長方法無關，一槪需要.75 0 °C以上之 高溫。欲藉利用三乙基硼（（C2H5)3B)/膦（PH3)/氫（112)反 應系之常壓（約爲大氣壓）或減壓MOCVD方法以得出單 結晶之BP層，適當之溫度係爲75 0 °C以上1200 °C以F (參照美國專利US-6,0 69,02 1號）。換言之，基板材料須 由具有在這樣高溫下不會變質之耐熱性之結晶選出。具 有在此高溫領域下之耐熱性之基板材料，計有磷化硼 (BP)單結晶（參照（1)上述之 Z.anorg· allg· Chem·，349(1967)， (2)Kristall und Technik，2(4)(1967)，第 523 〜534 頁，（3) Kristall und technik，4(4) 1 969)，第 4 8 7〜493 頁），及（4)上 -21 - 559899 五、發明說明（2〇) 述之 J. Electro Chem.Soc.，120(1973))。藍寶石（α -Α12〇3)，碳化矽（SiC)(參照上述之 J· Appl Phys.，42(l) (197 1)，以及矽（矽單結晶）之例。超過1200°C之高溫， 以分子式B6P和B13P2記述之磷化硼之多量體變成容易 形成（參照 J.Am Ceram. Soc.，47(l)(1964)，第 44〜46 頁）’ 但不利於得出由單量體之磷化硼（b 〇 r ο n m ο η 〇 p h 〇 s p h i d e) 作成之單結晶層。能自單結晶之BP層或BP系混晶層構 成，例如，TEGFET之電子供給層。另外，能構成LED 或L D之障壁層。生長之B P層或者其混晶層之結晶形 態（構造）一般係藉X光線繞射法（XRD)和電子線繞射法 所產生之繞射型樣（diffraction patter η)而得知。斑點 (spot)狀之繞射點係由單結晶造成（參照，J· Crystal Growth，70 ( 1 984)，第 5 07 〜514 頁）。 另外，依同一反應系之MOCVD方法，欲得出非均質 或多結晶之B P結晶層，適當之溫度係爲2 5 0 °C〜7 5 0 °C 之較低溫度（參照上述之US-6,069,021號以非晶質 (a m 〇 r p h 〇 u s )爲主體作成之B P層或B P系混晶層，當形 成含有與在基板上形成基板之結晶在晶格上甚不匹配 (mismatch)之生長層之磷系半導體元件用途之積層構造 體之際，具有發揮緩和晶格不匹配性之作用，進而實現 結晶性優良之生長層之效果。另外，具有有效地防止主 要因基板材料和生長層之熱膨脹係數之差異而造成生長 層從基板表面剝離之功用。因此，例如，以非晶質作爲主 -22- 559899 五、發明說明（21) 體之B P層能用做爲構成磷系半導體元件之緩衝層。另 外，緩衝層也能由，例如，在以低溫生長之非晶質之磷 化硼層上疊積以更高溫生長之磷化硼（B P)之單結晶層之 積層構造體而構成（參照上述之美國專利U S - 6，0 2 9，0 2 1 號）。即使當使用與BP在晶格上有不匹配關係之基板之 際，只要中間有介設非晶質之BP時則能簡便地得出結 晶性優良之BP單結晶層。例如，磷化硼系半導體發光 元件，具有能自積層構造作成之緩衝層上構成獲得高強 度發光之發光部之優點。另外，例如，磷化硼系HBT， 有助於能在積層構造之緩衝層上得出因晶格不匹配所引 起之不配合（misfit)轉變等之結晶缺陷少之良質集極層或 畐丨J 集極（sub-collector) 〇 從BP系混晶層能構成與單結晶基板進行晶格匹配之 生長層。例如，硼組成比爲0.02(磷化硼混晶比=2%)之 磷化硼·鎵混晶（Bo.^Gao 98P)(參照日本專利申請公報特 開平1 1 -266006號說明書）係爲晶格常數爲5.43 09A之 BP系混晶層。因此，從Bo.c2Gao.98P(參照上述日本專利 申請公報特開平1 1 -26 600 6號公報）能構成與Si單結晶 (晶格常數=5.4 3 0 9 A)晶格匹配之生長層與做爲基板之Si 單結晶晶格匹配之生長層也能從BP混晶比作成33%之 磷化硼銦混晶（BG.33In〇.67P)構成。從與基板行晶格匹配 之ΒΡ系混晶生長層能構成，例如，良質之緩衝。另 外，能構成呈現適於得出高積靈敏度之赫爾（hall)元件 -23- 559899 五、發明說明（22) 之高電子移動度之磁感層。另外，能適宜地利用於受光 兀件之光透射層（window層）。 具備由本發明之磷化硼（B P)作成之半導體之半導體元 件係利用室溫之帶隙爲2.8電子伏特（eV)以上3.4eV以 下之磷化硼（BP)之半導體層構成。另外，具備由本發明 之磷化硼（BP)系混晶作成之半導體層之半導體元件係利 用含有室溫時之帶隙爲2.8電子伏特（eV)以上3.4eV以 下之BP構成之BP系混晶半導體層而構成。室溫係約 2 0°C。亦即，係利用帶隙大於以往之BP者之2eV，但 非以往報告之4.2eV〜6.0eV那樣高，而係具有以往不知 曉之中間帶隙之BP或BP混晶層以構成BP系半導體元 件。室溫時之帶隙爲2.8 e V以上3.4 e V以下之磷化硼 (BP)層能藉規定其成長條件而形成。特別是，能藉將生 長速度和原料之供給比率兩者設定在規定之範圍而形 成。磷化硼（BP)層或BP系混晶層之生長速度良好地係 在每分鐘20A以上3 00A以下。生長速度若爲2〇A/min 以下之緩慢速度時則無法充份地抑制磷（P)構成元素或其 化合物從生長層表面脫離，揮發，結果會有無法達到成 膜之情形。若設定爲超過3 0 0 A / m i η之快速生長速度時 得出之帶隙値不安定，不理想。另外，若只徒然提高生 長速度時則易傾向產生多結晶之結晶層，不良於得出單 結晶層。 另外，配合生長速度，良好之原料之供給比率係規定 -24- 559899 五、發明說明（23) 在15以上，60以下之範圍。形成BP層之情形’原料 之供給比率係指對生長反應系’磷（P)源之供給量與硼源 之供給量之比率。另外’若係爲形成BP系混晶之情形 時係指含鱗（P)之v族元素源之合計對含硼（B)之111族 元素源之合計之供給量之比率。若以形成磷化硼·銦 (BxInuPiO^XSl)混晶爲例時則係指對生長反應系，磷 (P)源之供給量對硼（B)源和銦（In)源之總量之比率。亦 即，係爲所謂V/III比率。V/III比率若未滿15那樣小 時生長層表面會產生不欲有之雜亂。相反地，若πι/ν 比率超過60那樣極端大時從化學量理論觀之，容易形 成富磷（Ρ)狀態之生長層。過剩之磷（Ρ)進入在結晶晶格 上硼（Β)應佔據之位置，而成爲給與體（donor)(參照庄野 克房著「超LSI時代之半導體技術100集[5]」（歐姆社 (公司）昭和59年5月1日發行，電子雜誌電子 (electronic)第29卷第5號（昭和59年5月號）附錄，第 1 2 1頁）。BP或BP系混晶所屬之閃鋅礦型結晶原本具備 容易得出P形半導體層之帶隙縮小之價電子帶構造（參 照生駒俊明，生駒英明共著「化合物半導體之基礎性入 門」培風館（公司）1991年9月10日發行初版，第14〜17 頁）。雖然如此，但是化學量理論上之組成係形成富磷（P) 之趨勢，因此導致阻礙形成低電阻之P形結晶層之不良情況。 檢討以往之氣相成長方法上之BP層之形成條件，乙 硼烷（B 2 Η 6) /膦（Ρ Η 3) /氫（Η 2)系之氫化物法，有記述生長 -25- 559899 五、發明說明（24) 速度約達12〇A/min〜約70〇A/min之情形（參照上述之 Jpn. J. Appl，Phys.，1 3 ( 1 974))。另外，此氫化物生長法 指出欲生長BP層，V/III比率（ = PH3/B2H6須約爲50以 上（參照上述之Jpn J. Appl Phys.，1 3 ( 1 974)。特別是，記 述欲得出單結晶之BP層，須增加V/III比率至25 0(參 照上述之 Jpn· J. Appl. Phys.，1 3 ( 1 974))。另外，在以乙 硼烷和膦做爲原料形成BP層之其它例，生長速度最低 須設定於400A/min(參照庄野克房著「半導體技術 (上）」（東京大學出版會（財團法人）1 992年6月25日發 行第9次印刷），第74〜77頁）。欲得到呈現半導體性質 之BP層，V/III須要100倍以上（參照上述之「半導體 技術（上）」，第76〜77頁）。因此，以往之B2H6/PH3/H2 系氫化物法未達到本發明所言之低生長速度能採用，且 同時V/III比率滿足本發明之規定範圍者。 另外，以氯化物爲原料之鹵化物法，V/III比率雖設定 成滿足本發明之範圍，但做爲原料之鹵化物在進行氣相生 長時因分解所產生之鹵化物使生長中之BP層或Si層板本 身受到侵蝕，導致具有難於得到平坦表面之B P層之問 題。在同時滿足本發明規定之生長速率和V/III比率兩者 之條件下，適宜地生長BP層或BP系混晶層者蓋爲 Μ Ο C V D法。特別是，能良好地利用以三經基硼（t r i a 1 k y 1 boron)化合物爲硼（B)源之MOCVD法（參照上述之inst. Phys· Conf· Ser.，No.l29)。而在三羥基硼化合物中特別是 -26- 559899 五、發明說明（25) 使用三乙基硼（（C2H〇3B)之MOCVD法能簡便地在低溫了、· 執行非晶質之BP層或者BP系混晶層之形成，另外也能在 高溫下執行單結晶層之形成。三甲基硼（（H3)3B)係與硼院 和乙硼烷相同在常溫時係爲氣體，要在低溫下形成BP層 或者BP結晶層，並不如三甲基硼那樣適宜。欲要在低溫 下形成BP層或BP結晶層適宜做爲硼（B)源者係爲沸點 Μ ’常溫下爲液體之有機硼化合物。 例如，利用三乙基硼/膦/氫MOCVD反應系以形成磷 化硼（ΒΡ)單結晶層之際，生長溫度希爲85(TC以上1150。(： 以下。更理想者，係爲90(TC以上1100°C以下。等別 是，良好之溫度係爲95 0T：〜l〇5〇t：。例如，在9 5 0 °C下 設定V/III比率爲30時能安定地得出帶隙爲2.9eV之磷 化硼（BP)單結晶層。帶隙（ = Eg)，例如，係自一般之光冷 光（photo luminescence:PL)法，陰極冷光（cathode 1 u m i n e s c e n c e : C L)，或者吸收係數和光子（p h o t ο η)能量之 關係（參照上述之Zeager著「半導體之物理學（下）」， 第390〜450頁）求出。第2圖係不出在具有以上述之條 件添加硼（B)之P形之（1 Π)面之Si單結晶基板表面上未 摻雜（Un-dope)BP層之光子能量對吸收係數（absorption c(Efficient)之依存性。自吸收係數（a: cm 1和光子能量 (hv:eV)之關係求出之室溫下之帶隙約爲3. leV。亦即， 有關B P結晶，帶隙依溫度之變化率（溫度係數）已知悉 係爲每單元絕對溫度負（-)4.5x1 0_4eV(參照上述之Z. -27- 559899 五、發明說明（26) anorg. Allg. Chem.，3 49(l 967))。此溫度係數之負號係指 溫度愈低，帶隙愈高之意。因此，例如，在液體氮溫度 ( = 77K)下之BP層之帶隙係約爲3.2eV。這樣子，藉將生 長速度和V/III比率作成在本發明之規定範圍內，能得 出本發明之BP層。 另外，第3圖係示出利用與上述相同之MOCVD反應 系，在溫度爲95 0°C下生長速度和V/III比率分別設定 爲lOOA/min及60而生長之鎂（M.g)摻雜之P形磷化硼 (BP)層之CL光譜之例。該光譜係在溫度爲30K下被測 光得出者。磷化硼（BP)因係爲間接遷移型半導體，故 CL光譜適於在77K或更低之溫度下取得。做爲試料之 P形BP層之載體濃度約爲8χ1018 αιΤ3。另外，層厚係 約爲2.2 // m。第3圖示出之CL光譜之成份若藉利用一 般之尖峰（peak)分離法解析時係爲尖峰波長約爲3 78 5A 之光譜（第3圖中之記號「SP 1」所示），和尖峰波長約 爲5696A之光譜（記號「SP2」所示）。「SP2」可推測係 因「深」雜質位準所造成之光譜。另外，「SP2」所表 示之光譜之特徵爲確認其發光強度係與時減少。另外一 方面，「SP 1」係被推測爲帶端吸收之光譜，可自其尖 峰波長（3 7 8 5 A)算出約爲3.2eV之帶隙。 若舉依三乙基硼（（C2H5)3B)/膦（PH3)/氫（H2)系之 MOCVD方法生長之未摻雜之磷化硼（BP)層爲例說明時 一般非晶質層具有高的帶隙。特別是，例如，含有因與 -28- 559899 五、發明說明（27) 基底層晶格不匹配所引起之失真之BP非晶質層之室溫 時之帶隙一般有變大爲3.0 e V至3.4 e V之情形。增大生 長速度而生長之BP多結晶層一般帶隙有變小之趨勢。 特別是，層厚大於約2〜3 “ m之膜，帶隙有降低至約爲 2.8eV到3.0 eV之情形。另外，在上述適宜範圍之生長 速度及V/III比率之條件下生長之單結晶之BP層，能得 出介於非晶質層和多結晶層之中間帶隙。 利用具有本發明之帶隙之磷化硼（BP)，能形成具備從 來沒有之帶隙，並以一般式BaAlpGaym ·α_β_γΡ §AseN 1 _δ-ε (〇<α£ΐ)，0<β<1 » 0<γ<1 » 0<(χ + β + γ=1，〇<δ<1 > 0<ε<1 » 〇$δ + ε^1)記述之ΒΡ系混晶。例如，利用帶隙爲2.8eV 以上3_4eV以下之本發明有關之磷化硼（BP)，能形成室 溫時之帶隙爲1 .5eV以上3.4eV以下之磷砷化硼混晶（B ΡδΑ5ε:0<δ<1 ’ 〇<ε<1 ’ δ + ε=1)。使用帶隙爲約 2.0eV 之 以往之BP結晶，只能形成具有砷化硼（B a s)之帶隙約爲 1 .5eV以上（參照上述之「ΠΙ_ν族化合物半導體」，第 150頁），磷化硼（ΒΡ)之帶隙約爲2.0eV那樣之窄範圍之 帶隙之 Β Ρ δ A s 混晶（0 < δ < 1，0 < ε < 1，δ + ε = 1 )。另外，利 用帶隙爲2.8eV以上3.4eV以下之本發明有關之磷化硼 (BP) ’能形成室溫時之帶隙爲2.3eV以上3.4eV以下之 磷化硼·鎵混晶（BxGa^xP: 0<X<1)。因磷化鎵（GaP)之室 溫時之帶隙係爲2 · 3 e V (參照上述之「半導體槪論」，第 2 8頁），若藉與磷化硼（B P)進行混晶以增大B P之混晶比 -29- 559899 五、發明說明（28) 時亦即，藉增加硼（B)之組成比（ = X)，能形成2.3 eV以上 之（BxGanPiiXXcl)之混晶。但是，利用帶隙爲2.0eV 之以往之BP形成之BxGauPWKl)之混晶僅能形成 具有約2.0eV以上2.3eV以下之窄範圍之帶隙之BxGa^xPacXd) 之混晶。如B X G a 1 _ X P (0 < X < 1 )之混晶那樣，具有從不含 砷做爲構成元素之BP系混晶，能構成已考慮防止對環 境造成污染之磷化硼系半導體元件之優點。 從帶隙爲2.8eV以上3.4eV以下之本發明之BP結晶 構成之BP系混晶，如上述之例具備以往之BP系混晶沒 有之廣範圍，且高之帶隙。因此之故，例如，對爲了放 射短波長光而設置之發光層構成障壁層方面係特別有 用。例如，自硼組成比（ = X)爲0.90之Βο.μΑΙο.μΡ混晶 能對由立面體晶之氮化鎵·銦之混晶（Ga〇.75In().25N)作成 之發光層構成障壁層。另外，磷化硼（BP)或者BP系之 混晶係爲閃鋅礦型之結晶，係處於能容易自其價電子帶 之帶構造（參照上述之「化合物半導體之基礎性入門」） 獲得P形層之狀況。因此，例如，與六面體之氮化鎵（h-GaN)之狀況不同，能簡便地形成P形且低電阻之障壁 層。從立面體晶之GamInmN之發光層放射接近發光 波長爲443 0A之藍紫色之近紫外光，因此，具有能從 Bo.qqAIugP之混晶和Ga〇.75In().25N之混晶作成之異類接 合構造構成具有單一（single)或者雙重（double)異類接合 構造之藍色帶發光之pn接合型發光部之優點。更甚 -30- 559899 五、發明說明（29) .者，BG.9GA1().1()P混晶和Ga〇.75In().25N之混晶係用具有相 同之晶格常數（ = 4.62 8 A)(立面體晶之氮化銦（InN)之晶格 常數係以4.9 8 A計算：參照上述之「111 - V族化合物半導 體」，第3 3 0頁）。換言之，從本發明之BP混晶因能構 成與發光層行晶格匹配之障壁層，故能構成晶格匹配系 之發光部。具有相互晶格匹配關係之結晶層則成爲少因 晶格匹配所造成之結晶缺陷之良質結晶層。因此之故， 逐從晶格匹配系之發光部射出高強度之發光，進而有助 於實現高亮度之磷化硼系半導體發光元件。再者，具有 相互晶格匹配關係之結晶層係指具有晶格不匹配度在 ±0.4%以下之關係之結晶層。 另外，使用本發明之磷化硼（BP)層或BP系混晶層， 可便利構成成爲適於構成LED或LD之晶格匹配系之發 光部。例如，從由η形成p形磷化硼（BP:晶格常數： 4.5 3 8 Α)作成之障壁層及自磷（Ρ)之組成比爲0.03磷氮 化鎵（GaNQ.97P().(H:晶格常數=4.5 3 8 Α)混晶作成發光層能 構成晶格匹配系之，例如，pn接合型發光部。另外，從 由碟組成比爲〇 . 1 〇之面體晶/<£ G a N 〇 9 ο Ρ ο 1 ()作成Z發 光層及由鎵（Ga)組成比爲0.07之立面體晶之磷化硼·鎵 (B0.93Ga0.07P)作成之障壁層，能簡便地構成晶格匹配系 之發光部。同樣地，利用氮砷化鎵（GaNuAsxiOSXy) 作發光層，亦能構成晶格匹配系發光部。但是，相對於 氮化鎵（GaN)之生長能量在標準狀態下爲（―）26.2Kcal/ -31 - 559899 五、發明說明（3〇) mol，GaAs之生長能量則較大爲（―）19.2kcal/mol。（參 照日本專利申請公報特開平1 0- 5 348 7號說明書）。另外 一方面，GaP之生長能量係比（—）29.2kcal/mol，及GaN 之生長能量小（參照上述之日本專利申請公報特開平1 0-53487號）。因此之故，相較於GaNi.xASx混晶，GaNuPx混 晶良好地能容易形成。障壁層，相對於GaN, _XPX發光 層，係由具有較大室溫時之帶隙之BP層或BP系混晶層 構成。從約爲（KleV以上，最好爲0.3 eV以上之高帶隙 之BP層或BP系混晶層能構成障壁作用充份地及於發光 層之障壁層。 另外，本發明之磷化硼（BP)或BP系混晶，如上述那 樣，具備能大幅透射短波長之可視光之帶隙。因此之 故，例如，調整硼組成比（ = X)俾得有2.7eV以上之帶隙 之BxGai_xP(利用室溫時之帶隙爲3.0eV之BP結晶時係 爲〇.4^Χ<1)，能良好地構成透射比發光波長約爲4 5 90 A長之波長之LED發光透射層（window)。另外，從帶隙 爲2.8eV以上3.4eV以下之範圍之磷化硼·銦（ΒχΙηι-χΡ) 混晶，能利用作成能透射比約4430 Α長之波長之發光 LED或面發光型LD (參照伊賀，小山共著『面發光雷 射」（歐姆（公司），1 990年9月25日發行，第1版第1 次印刷），第4〜5頁）。另外，能用於構成LED或者面發 光雷射（surface emitting laser)用途之反射鏡（參照上述 之「面發光雷」，第118〜119頁）。 -32- 559899 五、發明說明（31) 從由較容易生長之G aN i _ X P X混晶和本發明之B P層或 者BP系混晶構成之積層構造體能構成受光元件用途之 受光部。例如，磷化硼（BP)或BP系混晶層和與這些層 之晶格不匹配度爲0.4%以下之半導體層之接合構造體能 構成信號/雜音強度比，亦即，S/N比大，受光靈敏度優 之受光元件用途之受光部。特別是，例如，利用磷化硼 (BP)層和與此層行晶格匹配之半導體層，例如，從與上 述之GaN^Px層行異類接合之構造體作成之受光部， 能構成空轉電流（i d 1 i n g c u r 1· e n t)低受光度優之高靈敏度 受光元件用途之受光部。另外，本發明之BP層或BP系 混晶層有用於作爲能有效率地將測光對象導入受光層之 光透射層。特別是，具備以往沒有之2.8eV以上之比較 高範圍之帶隙之BP層或BP系混晶層連藍色等之短波長 可視光也能有效率地透射，因此，能有效地用於將短波 長可視光做爲測光對象之受光元件之窗層。 由磷化硼（BP)層或BP系混晶層和與這些層行晶格匹 配之半導體層作成之異類接合構造，具有能使載體，例 如電子，高速地移動（transport)之優越性。例如，BP層 或BP系混晶層和GaN^Px混晶之異類接合構造體係適 宜用於構成需要電子之高速移動性之TEGFET之功能層 這種情形，直接遷移型之G aN i _ X P X混晶層能顯現出高 電子移動度，因此，特別適用於構成TEGFET之電f行 走層。另外，從BP層或BP系混晶層能構成與電子行走層 -33- 559899 五、發明說明（32) 行異類接合’以構成獲得在電子行走層內供給電子之作 用之電子供給層。另外，從本發明之B P層或B P系混晶 層也能構成配置在電子供給層和電子行走層之中間之間 隔（spacer)層。電子供給層或者間隔層之帶隙最好係由 比電子行走層之構成材料者大約〇.2eV以上，最好爲約 0.3eV 以上，以一般式 BaAlpGaylm.a.piPsASeNne (0<α<150<β<1 » 0<γ< 1 » 0<α + β + γ<1 » 〇<δ< 1，0<ε< 1， 0<δ + ε$1)記述之半導體層構成。特別是，GaN丨_χ Ρχ混 晶層因上述之理由較砷化物容易形成。 另外，若利用依GaNuPx混晶之磷（Ρ)組成比而成之 帶隙之曲折（bowing)(參照 Appl Phys Lett., 60(20)(1992)， 第2540〜2 542頁），藉改變在直接遷移之領域上之磷（p) 之組成數°/。程度，能改變帶隙。例如，若磷（P)之組成比 爲5°/。時則能使帶隙自3.2^降低至約2.86¥。亦即，具 有從GaN^Px混晶，能對應磷（P)之組成比簡便地構成 顯現出與由BP層或BP系混晶層作成之間隔層或電子供 給層之帶隙相差上述那樣良好之帶隙之電子行走層之優 點。 例如，如第4圖所示之模式例，在由面方位爲（000 1 ) (C面）之藍寶石（s a p p h i r e)作成之基板4 0 1上，例如，依 (1)由2.8eV以上，3.4eV以下範圍內良好地爲3eV以 上，之帶隙層厚（ = d)約爲100A之未摻雜之高電阻磷化 硼.銘（8\人11_)^:〇<乂<1)作成之非晶質作爲主體之低溫緩 -34- 五、發明說明（33) 衝層402， (2) 由在比低溫緩衝層402高之溫度下形成之，良好 地帶隙爲3eV以上，例如，載體濃度（ = n)約未滿5xl015 cm ，d = 3 00A之未摻雜之η形BP作成之高溫緩衝層 4 0 3， (3) 由與作成高溫緩衝層403之BP行晶格匹配，且帶 隙更小之，例如，多面體未摻雜η形GaNo.^Po.od例 如，n = 5xl016 cm _3，d = 2 5〇A)構成之電子行走層404， (4) 由良好地帶隙爲3eV以上，具有比電子行走層104 高之帶隙之，例如，載體濃度（ = n)約未滿5xl015 cnT3， d = 5 0 A之摻雜之η形B P作成之間隔層4 0 5， (5) 由良好地帶隙爲3eV以上之，例如，載體濃度（ = n) 約未滿2xl018 cn厂3，d = 25〇A之矽（Si)之摻雜η形BP作 成之電子供給層406， (6) 由良好地帶隙係爲在電子供給層406者以下之， 例如，載體濃度（ = n)約爲5xl018 cnT3，d = 15〇A之矽（Si) 之摻雜η形BP作成之歐姆電極接觸層407， 各層順序疊積以形成TEGFET40用途之積層構造體 4 1。接著，在接觸層4 0 7之一部份上施予凹陷（r e c e s s ) 加工，並在該凹部內設置肖特基（Schottky)接合型閘 (gate)電極40 8。另外，在凹部41 1兩側剩餘之接觸層 4 0 7之表面上形成歐姆（〇 h m i c)性之源極（s 〇 u r c e )電極4 0 9 及洩極（drain)電極410，進而構成TEGFET40。 -35- 559899 五、發明說明（34 ) 另外，在磷化硼（BP)或BP系混晶上積層之，例如， GaNuPx混晶層能被利用做爲赫爾（hall)元件磁感部。 特別是，直接遷移型，非間接遷移型之，例如，GaNu Ρχ混晶層能被利用做爲赫爾元件磁感層（磁氣感應層）。 再者’ GaN卜χ Ρ X混晶層能採用比構成以往之赫爾元件之 磁感層之銻化銦（InSb，帶隙=0.18eV)或者砷化銦 (InAs，帶隙= 〇.3 6eV)或砷化鎵（GaAs，帶隙=1 .43eVH£ 何一種（有關室溫時之帶隙，參照上述之「III-V族化合 物半導體」，第1 5 0頁），磷組成比都大之帶隙（參照上 述之Appl. Phys Lett.，6 0( 1 9 92))。帶隙大之半導體材 料，到達傳導性上之因有領域之溫度變成更高（參照上 述之「半導體之物理學（上）」，第5〜10頁），因此，有 利於構成能在高溫下動作之赫爾元件。由採用比GaN 1 .X Asx混晶者高之帶隙之，例如GaN^xPx混晶，能構成在 更高溫下能動作之元件之磁感層。因此，從自GaN^Px 混晶層和BP層或BP系混晶層作成之異類接合構造體’ 具有能構成在高溫下也能動作之耐環境型之赫爾元件之 優點。特別是，與BP層或BP系混晶層行晶格匹配之直 接遷移型之11形GaN 1-χρχ混晶層達成更高之電子移動 度，因此，能有助於得出高靈敏度，且能在高溫下動作 之耐環境型赫爾兀件。 本發明有關之赫爾元件係由共板和含有例如緩衝層與 磁感層之積層構造體所構成。第5圖之斷面圖係示出本 -36- 559899 五、發明說明（35) 發明有關之耐環境型之赫爾元件用途之積層構造體之 例。基板5 01係利用，例如，矽，藍寶石，或者碳化矽 (SiC)等之單結晶。設在單結晶板501上之第1緩衝層 5 〇2係由在低溫下生長之，例如，非晶質之n形磷化硼 (Β Ρ)構成。第2緩衝層5 0 3係由在比第1緩衝層5 0 2高 之溫度下生長之，例如，矽（Si)摻雜之η形ΒΡ單結晶層 構成。磁感層5 04係由與磷化硼（ΒΡ)(融點：3 000 °C )(參 照上述之「半導體裝置槪論」，第28頁）同樣高融點之 氮化鎵（G aN :六面體晶h - G aN之融點> 1 7 0 0 °C (參照上述 之「半導體裝置槪論」）或者磷氮化鎵（GaN^xP^iXXci) 等構成。磁感層504最好由與基底層（若係第5圖之積 層構造系時係爲第2緩衝層5 03 )晶格不匹配少，且行晶 格匹配之材料構成。晶格不匹配度之絕對値（△:單位 係以下式由基底層之晶格常數（ = aQ)和堆積層之晶格常數 ( = a)算出。 Δ(%) = | (a- a〇)/ a〇 | χ100 立面體晶之GaN(a = 4.5l〇A)和ΒΡ單結晶（a〇 = 4.5 3 8 A)之 晶格不匹配係僅爲0 · 6%，成爲適於構成磁感層之材料。 另外，在本構成例之已成長（as-grown)之狀態下以非晶 質爲主體作成之緩衝層（第5圖之第1之5 02)具有緩和 晶格不匹配之作用，進而有助於更提高上層之結晶性。 再者，氮組成比爲〇·〇3之磷氮化鎵（GaNuPo. 〇3)之晶 格常數係與BP單結晶一致，爲4.5 3 8 A。從這樣行晶格 •37- 559899 五、發明說明（36) 匹配之材料作成之磁感層’因晶格不匹配所引起之不配 合（misfit)轉變等之結晶缺陷密度低，進而成爲良質之結 晶層。因此，藉能呈現出高度之移動式提供耐熱性優良 之高靈敏度之赫爾元件。例如，藉三乙基硼（（C2H5)3B)/ 膦（PH3)/氨（NH3)/氫（H2)系常壓MOCVD法，在面方位爲 (100)之磷（P)摻雜之η形Si單結晶基板501之表面上順 序地疊積下述之生長層。 (1) 由層厚（ = d)約爲70A，室溫時之帶隙約爲3.1eV之 未摻雜（un-dope)之η形BP層作成之第1緩衝層502。 (2) 由載體濃度（ = η)約爲6x1 Ο15 αι厂3，室溫時帶隙約爲 3.0eV之η形之ΒΡ層作成之第2緩衝層5 0 3 (d = 0.7 // m)。 (3) 由d = 0.1//m，n = 2xl016 cm ，室溫時之移動度約 爲8 5 0 cm 2/V*S之立面體晶之η形GaNo.97Po.G3作成之 磁感層5 04，接著，藉甲烷（methane)(CH4)/氬（Ar)/氫（Η2) 系之電漿浸蝕措施，對磁感層504進行台地（mesa)加 工。再者，於做爲磁感部（Hall cross部）而殘存十字形 之磁感層5 04之4端上敷設由例如金（Au)或Au合金等 作成之歐姆電極。從這樣之構成能提供積靈敏度 (p r 〇 d u c t s e n s i t i v i t y)在室溫下約爲 1 5 m V / m A · K G 之耐環 境用之高靈敏度之赫爾元件。 本發明有關之磷化硼（BP)因係爲有大於以往之帶隙 (約爲2eV)之大帶隙，故能自本發明之BP構成以往沒有 之大帶隙之BP系混晶。因此之故，在與帶隙不同之其 -38- 559899 五、發明說明（37) 它之半導體層作成異類接合構成之際，能擴大其自由 度’進而能顯現各種之異類接合構造。例如，以往之小 帶隙之BP(帶隙2eV)，對與BP行晶格匹配之GaNQ 97 Ρ ο · 〇3 (帶隙3 e V )’無法作成施予障壁作用所需之異類接 合構造。另外一方面，從本發明有關之B P，特別是從 大於3eV帶隙之BP，因能構成對GaN〇.97 Ρϋ.ϋ3施予障 壁作用之障壁層，故能作成呈現載體（carrier)之「關 入」效果之晶格匹配系異類接合構造體。從這樣之異類 接合體，如上述那樣，變成有用於獲得耐環境型之 TEGFET和赫爾元件等之異類接合裝置。 TEGFET若利 用本發明有關之帶隙大之BP或BP系混晶做爲緩衝層時 特別能抑制閘極電流之洩漏，因此，亦能獲得相互電導 (gm) (mutual conductance)優良之 TEGFET。另外，赫爾 元件，若由本發明所述之帶隙大之B P或者B P系混晶構 成緩衝層時能抑制動作電流之洩漏，進而達到獲致積靈 敏度高之赫爾元件。 從本發明記載之BP或BP系混晶作成之半導體層， 因能呈現比以往者大之帶隙，故能創出多彩多樣之半導 體層和以往沒有之大偏移（b a η d - 〇 f f s e t)之異類接合構 造。使用本發明記載之BP或BP系混晶作成之半導體層 之異類接合構造因係爲如上述那樣之帶不連續性大之異 類接合構造，故特別優於被用爲障壁層。 (實施例） -39- 559899 五、發明說明（38) (實施例1) 本實施例1將舉使用本發明之BP半導體層之III族 氮化物半導體LED爲例具體地說明本發明。第6圖係模 式地示出本實施例1有關之Pn接合型LED 60之斷面構 造。 LED60用途之積層構造體61係用硼（B)摻雜之p形， 具有（1 1 1 )面之S i單結晶做爲基板6 0 1而構成。甚板 6 0 1上之低溫緩衝層6 0 2係由在已生長（a s - g 1· 〇 w η )之狀 態下之非晶質做主體之磷化硼（BP)構成。低溫緩衝層 602係藉三乙基硼（C2H5)3B)/膦（PH3)/氫（H2)系常壓 MOCVD法在3 5 0°C下生長。低溫緩衝層602之層厚約 爲 1 2 n m 0 在低溫緩衝層602之表面上利用上述之MOCVD氣相 生長方法疊積於9 5 0 °C溫度下摻入鎂（Mg)之p形BP層 以做爲下部障壁層603。鎂之摻雜源係使用二環戊：烯 基（c y c 1 〇 p e n t a d i e n y 1)鎂（b i s - (C 5 Η 5) 2 M g)。下部障壁層 603之載體濃度約爲7xl018 cnT3。層厚約爲0.8 // m。 做成下部障壁層603之BP層之室溫時之折射率 (index of refraction)和消衰係數（extinction coefficient) 對波長之依存性係如第7圖所示。得出比約45 Onm短之 波長側之消衰係數（ = k)有急劇增加之趨勢。例如，相對 於波長爲45 0 nm之折射率約爲3.21，消衰係數約爲 0.0 0 2 9，測得出波長爲 3 8 0 n m 時之 η = 3 . 2 8，k = 0 . Π 2 0。 -40- 559899 五、發明說明（39) 第8圖示出根據η及k値求出之複數介電率之虛數部 (ε2 = 2·η·]〇(參照上述之「III-V族化合物半導體」第 16 8〜17 1頁）與光子（photon)之能量之關係。呈現出ε2値 係隨著光子能量之增加而減少之現象。另外，自ε2値之 切片求出之光子能量約爲3.1eV。因此，圖上示出做成 下部障壁層6 0 3之磷化硼（BP)結晶之室溫時之帶隙係約 爲 3.1eV。 在室溫時之帶隙約爲3 . 1 eV之BP下部障壁層6 0 3上 疊積與磷化硼（BP)行晶格匹配，磷組成比爲0.03( = 3%) 之摻鎂之p形憐氮化鎵（GaN〇.97P〇.()3)層以做爲發光層 604。做成下部障壁層603之BP與由GaN〇.97P〇.〇3作成 之發光層（室溫時之帶隙爲2.9eV)之帶隙之差異約爲 0.2eV。由立面體晶之GaN〇.97P().()3作成之發光層604係 藉三甲基鎵（（CH3)3Ga)/PH3/H2系常壓MOCVD法在950 °C之溫度下生長。發光層604之載體濃度約爲3x1 01 7 cm _3。層厚約爲0.3 // m。 在發光層6 0 4上疊積層厚約爲〇 · 3 // m之η形磷化硼 (Β Ρ )以做爲上部障壁層6 0 5。上部障壁層6 0 5係藉 (C2H5)3B/PH3/H2系常壓M0CVD法於9 5 0 °C下生長。上 部障壁層605之晶格常數爲4· 5 3 8 A，上部障壁層605和 發光層6 0 4之晶格常數係作成一致。上部障壁層6 0 5也 是與下部障壁層603 —樣由室溫時之帶隙約爲3. leV之 BP結晶構成。上部障壁層60 5之載體濃度約爲2x1 018 -41 - 559899 五、發明說明（4〇) cm 。由上述帶隙約爲3 . 1 Ve之BP半導體層作成之下部 障壁層60 3及上部障壁層60 5係與由GaNmPo.in發光 層6 04作成之pn接合型構成雙重異類（DH)接合構造型 之發光部606。 在上部障壁層605上疊積由帶隙約爲3. leV之η形磷 化硼（Β Ρ)作成之電流擴散層6 0 7。做成電流擴散層6 0 7 之Si摻入層係藉（C2H5)3B/PH3/H2系常壓MOVCD法， 在9 5 0°C以下生長。設定電流擴散層6 7 0之層厚約爲 5〇nm，另外，載體濃度約爲8xl〇i8 C111 _3。 在ρ形Si單結晶基板601之底部表面上形成由鋁（A1) 作成之ρ形歐姆（ohim)電極609。另外，在電流擴散層 6 04表面中央上配置由金鍺（Au.Ge)合金作成之η形歐姆 電極6 0 8。η形歐姆電極6 0 8之直徑約爲1 3 0 // m。然後 將做爲基板601之Si單結晶在平行及垂直於[21 1]方向 裁斷，如此則得出一邊約爲3 0 0 /2 m之L E D晶片 (c h i ρ ) 6 0。 在兩個歐姆電極6 0 8〜6 0 9之間通以順面驅動用電流使 發光。電流-電壓（I-V特性）顯示出基於發光部60 6之良 好pn接合特性之正常整流特性。從i_V特性求出之順 向電壓（亦即Vf)約爲3.1V(順向電流=20mA)。另外，逆 向電壓約爲10V(逆向電流=5 // A)。當在順向上通以20 毫安培（mA)之動作電流之際則射出發光中心波長約爲 43 0nm之藍色光。發光光譜之半寬度（helfwidth)約爲 -42- 559899 五、發明說明（41) 2 3 n m。利用一*般之積分球測定之晶片狀態之發光強度約 爲1 4微瓦特（// W)，如此，提供高發光強度之B P系化 合物半導體LED。 (實施例2) 本實施例2係舉具備本發明記載之磷化硼（BP)層之pn 接合型二極體爲例，具體地說明本發明之內容。第9圖 係模式地示出本實施例/之pn接合型二極體90之斷面 構造。 在摻入磷（P)之η形且具有（111)面之Si單結晶基板 901上疊積藉乙硼烷（B2H6)/(CH3)3Ga/H2系減壓MOCVD 法在400°(：溫度下自磷化硼鎵（8)<0&1_)^)構成之低溫結 晶層902- 1。硼（B)組成比（ = X)係爲與Si單結晶（晶格常 數=5 · 4 3 1 A)行晶格匹配之〇 · 〇 2。低溫結晶層9 0 2 - 1係在 約爲1.3X104帕斯卡（pa)減壓下生長。低溫結晶層902-1之層厚係約爲4nm。 依斷面TEM法所作之觀察，成膜時之已生長（as-grown)狀態之Bo.wGao.98之低溫結晶層902 - 1，大約在 距與S i單結晶基9 0 1接合之面上方1 nm之領域係成爲 單結晶。另外，在BG.〇2Ga().98P之低溫結晶層902- 1和11 形S i單結晶基板9 0 1上保持良好密接性而無剝離之情 形產生。低溫結晶層9 0 2 - 1之上部係以非晶質體爲主體 而構成。 在Bo.wGao.98?低溫結晶層902」上，疊積利用上述 -43- 559899 五、發明說明（42) 之減壓MOCVD反應系，在95 0 °C之溫度下賦與硼組成 ( = X)組成斜率之摻Si之η形BxGauP之高溫結晶層 9 0 2 - 2。硼（B )之組成比係在高溫結晶層9 0 2 - 2之層厚之 增加方向上從〇 . 〇2到1 · 0作直線之增加。亦即’對硼（B ) 之組成賦與斜率，使η形高溫結晶層902-2之表面成爲 磷化硼（ΒΡ)層。被賦與這種組成斜率之η形BxGau P(X = 0.02到1 .0)層係以室溫時之帶隙約爲3 .OeV之BP 結晶爲基底構成，因此，成爲約有3 .OeV之結晶層。硼 (B)之組成斜率將供給至MOCVD反應系之乙硼烷 (diborane)之量與時遞增，相反地三甲基鎵（trimethyl g a 1 i u m)之供給量與時遞減。層厚約爲0.4 // m。η形高溫 結晶層9 02 _2在進行生長時反應系之壓力係設定於約 1.3xl04Pa。BxGa^P 組成斜率（Χ = 0·20 到 1.0)在生長 高溫結晶層9 0 2 - 2時係使用乙砂院（S i 2 Η 6) - Η 2之混合氣 體摻入S i。載體濃度係設定於約1 X 1 0 18 αι厂3。依X射 線之繞射分析法所作之解析確認η形高溫結晶層902-2 係爲（1 1 1)定向性之立面體晶之BxGa = 到0.1) 之結晶層。 在結束η形高溫結晶層902-2之BxGa^P之組成斜 率層之成膜後，Β〇 〇2〇8().98Ρ低溫結晶層902- 1內部之非 晶質體之大部份係以存在於與已生長（as-grown)狀態之 Si單結晶基板90 1接合之境界領域內之單結晶層爲基礎 而單結晶化。另外，η形BxGauPpzO.M到1 .〇)之高 溫結晶層902-2因係設在由與Si單結晶基板901行晶格 -44- 559899 五、發明說明（43) 匹配之組成之Bo.o2Gao.98P(晶格常數= 5.43 1 A)作成之低 溫結晶層9 0 2 - 1之上，故成爲不會剝離之連續膜。緩衝 層902係由上述之低溫及高溫結晶層902- 1，902-2之積 層構造所構成。 在η形高溫結晶層902-2上藉B2H6/PH3/H2系減壓 MOCVD法於95 0 °C溫度下接合η形磷化硼（BP)層903。 當生長η形ΒΡ層9 0 3時係使用Si2H6-H2混合氣體以摻 入Si。η形BP層9 0 3之載體濃度約爲5x1 017 C111~3。另 外，層厚約爲0.3 // m。η型層9 0 3係由室溫時之帶隙約 爲3.0eV之ΒΡ結晶構成。 在η形BP層903上藉B2H6/PH3/H2系減壓MOVCD 法於95(TC溫度下沉積p型BP層904。p形BP層904 係由摻入帶隙約爲3. OeV之鎂（Mg)之BP層構成。鎂之 摻雜源係利用二環戊二烯基Mg(bis-C5H5)2Mg)。p形層 9 04係由寬帶隙之半導體之閃鋅礦結晶型，且離子結合 性低之B P所構成，因此載體濃度能作成約爲3 X 1 0 1 8 cm _ 3。p形層9 0 4之層厚約爲0.2 // m。從上述之η形B P 層9 0 3和ρ形ΒΡ層9 04構成ρη接合構造。 在η形Si單結晶基板901之底部表面上形成由鋁（Α1) 作成之η形歐姆（〇 li m i c)電極9 0 6。另外，在p形B P層 9 04之表面之中央上配置由金（Au)作成之形歐姆電極 9 0 5。p形歐姆電極9 0 5之直徑約爲1 1 〇 " m。然後’將 作爲基板9 0 1之S i單結晶在平行及垂直於[2 1 1 ]方向之 -45- 559899 五、發明說明（44 ) 方向上裁斷’從而做成一邊約爲3 5 0 // m之二極體9 〇之 晶片（chip)。 弟1 0圖係不出在兩歐姆電極9 0 5〜9 0 6間通以順向電流 而測定之電流-電壓（I-V特性）之例。本實施例2之pil接合 型BP二極體呈現出基於良好pn接合特性之正常整流特 性。另外，逆向電壓係約爲15V(逆向電流=1〇 # a)，從而 提供高耐壓之化合物半導體pn接合型二極體。 (實施例3) 本實施例3係以具備含有本發明之磷化硼（BP)之bp 系混晶之npn接合型異類雙極性電晶體（HBT)爲例具體 地說明本發明之內容。第1 1圖係示出本實施例3之npn 接合型HBT之斷面模式圖。 在係爲磷（P)摻雜之η形且具有面1 〇 〇之S i單結晶基 板101上藉乙硼烷（B2H6)/(CH3)3Ga/H2系減壓MOCVD 法，於3 5 0 °C之溫度下疊積由磷化硼·鎵（BxGai_xP)構成 之低溫緩衝層102。硼（B)組成比（ = X)係作成爲Si單結 晶（晶格常數=5.43 1A)行晶格匹配之〇.〇2。低溫緩衝層 102係在約爲1.3x1 04帕斯卡（Pa)之減壓下生長。低溫 緩衝層之層厚約爲l4nm。 在Bo.wGao.^P之低溫緩衝層1〇2上，利用上述之減 壓Μ Ο C V D反應系，於生長溫度固定於8 5 0 °C下，順序 地疊積下述之各個功能層。各功能層1 0 3〜1 0 8之載體濃 度（n(n形）或P(P形））及層厚⑴係分別作成如下述那 -46- 559899 五、發明說明（45) 樣，從而構成如HB Τ 1 0之用途之積層構造體1 1。 (1) 從與BP低溫緩衝層1〇2接合之界面朝層表面將硼 ( = X)之組成比自0.02直線地增加到1.0。即從表面爲磷 化硼（BP)之Si摻雜n形BxGa^P組成斜率層作成之集 極層 1 0 3 (η = 9 X 1 0 17 cm，t = 0.5 0 // m)。 (2) 由 n = 2xl018cnT3，t = 0.10//m 之 Si 摻雜 η 形 BP 作成之副（sub)集極層104。 (3) 由 n = 3xl018 cm ·3，t = 0.05//m 之立面體晶之 Si 摻 雜η形氮化鎵（G aN )作成之中間層1 〇 5。 (4) 由p = 3xl019⑽，t = 0.0 1 // m，室溫之帶隙約爲 3eV之鎂（Mg)摻雜之p形磷氮化硼（BPg.97N().〇3)作成之 基極體1 〇 6。 (5)由 n = 4xl018 cm _3，t = 0.20 // m，室溫之帶源約爲 3.2eV之Si摻雜之η形氮化鎵（GaN)作成之射極層107。 (6)由n = 7xl018⑽_3，t = 0.10 // m，室溫之帶源約爲 3.2 e V之S i摻雜之η形氮化鎵（G aN )作成之接觸層 108。 然後藉利用氬（Ar)/甲烷（CH4)/氫（H2)混合氣體之一般 電漿浸蝕法對HBT用積層構造體1 1施予階段性浸蝕， 使露出集極層108，基極層106及副集極層104之各個 功能層之表面。上述之中間層1 05係對副集極層1 〇4賦 予阻止浸蝕之作用，藉此達到淸楚地裸露副集極層1 〇4 之表面之效果。 在集極層108之表面上設置由金·鍺（Au97重量％_Ge3 重量％)之合金作成之射極電極1 09。射極電極1 09之平__ -47- 559899 五、發明說明（46 ) 形狀係作成爲一邊之長度約爲1 1 0 // m之正方形。在藉 上述之侵蝕加工而露出之副集極層1 04上設置由與上述 相同之AtGe合金作成之集極電極110。η形層用之各 電極1 09，1 1 0係藉一般之真空蒸著法而被蒸著，接 著，在42 0 °C之溫度下進行5分鐘之合金化熱處理 (alloy)。然後，藉利用石板印刷技術之選擇性型樣化方 法在P形基極層106上設置由金·鋅（Au95重量％，Zn5 重量％)合金作成之帶狀基極電極111。然後，在400 °C 溫度下進行2分鐘之合金化熱處理。之後，將其裁斷成 各個半導體元件。 於得出之HBT射極電極109及集極電極1 10間施加 2.5V之電壓（所謂集極電壓）之狀態下使薄片（sheet)電阻 約爲3 60Ω/□之基極層106之基極電流在0至50微安培 (// A)之範圍內變化。對基極電流之變化幅度直流電流 放大率（P = IcE/UB)係約略一定爲95。藉此，依本發明能 提供直流放大率高，且安定之HBT。 (實施例4) 本實施例4，係以具備本發明之磷化硼（BP)半導體層 之紫外線領域用途之受光元件（photodetector)爲例具體 地說明本發明之內容。第1 2圖係示出本實施例4之受 光元件20之構成之斷面模式圖。 在具有（〇〇〇l)(C面）之藍寶石基板201上藉三乙基硼 ((C2H5)3B/PH3/H2系常壓（約略大氣壓）M0CVD法於380 -48- 559899 五、發明說明（47) 之溫度F堆積由磷化硼（BP)作成之低溫緩衝層202。低 溫緩衝層2 0 2之層厚約爲5 n m。於B P低溫緩衝層2 0 2 上利用上述之常壓Μ 0 C V D法於8 2 5 °C之溫度下堆積矽 (Si)摻雜之η形磷化硼（BP)主動層203，進而構成受光 元件20用之積層構造體21。主動層2 0 3係由室溫時之 帶隙約爲3.leV之ΒΡ半導體層構成。主動層203之載 體濃度約爲2xl01() on _3，層厚約爲1.8 // m。 然後將製成之受光元件用積層構造體2 1施予電漿浸 蝕，從而將主動層203之表面之中央部浸蝕成圓形狀。 浸蝕作業係對直徑約爲1 2 0 // m之圓形領域進行，浸蝕 之深度約爲0 . 1 A m。於此領域上，形成由直徑作成約 100 // m之鈦（Ti)/鉑（Pt)/金（Au)作成之三層構造之肖特 基（schottky)電極204。另外，在肖特基電極204之外圍 配置由金·鍺（Au.Ge)/鎳（Ni)/金（Au)三層構造形成之圓環 狀之歐姆電極205以構成受光元件20。圓環狀之電極 2〇5係形成在以上述之肖特基電極204之中央之中心之 直徑約爲2 2 0 // m之圓周上。 本實施例4因係以低溫緩衝層202做爲基底層再疊積 主動層2 0 3，故主動層2 0 3變成良質之結晶層，藉此， 將當對歐姆電極20 5和肖特基電極204間施加-2V之逆 向電壓時之空轉電流減少至lxl(T8A/cnT2程度。另外， 截斷（cut-off)波長約爲40nm，因此，依本發明，能提供 空轉電流特性優之近紫外線領域之受光元件。 -49- 559899 五、發明說明（48) (發明之效果） 依本發明，創作利用室溫時爲2 · 8 e v以上3 · 4 e V以 下，以往沒有之高帶隙範圍之磷化硼（BP)或藉與該βΡ 之結晶混晶化得出之ΒΡ系混晶構成化合物半導體元 件，因此具有依其寬廣帶隙性’能在高溫下動作，且能 構成高耐壓之半導體元件之效果。特別是，除了具有寬 廣之帶隙外，另係作成爲利用離子結合性小之閃鋅礦結 晶型之Β Ρ或Β Ρ系混晶’因此能簡便地形成局正孔濃度 之Ρ形傳導層從而具有能提供利用低電阻之Ρ形半導體 層做爲功能層之半導體元件。 從利用由本發明之ΒΡ作成之半導體層或由ΒΡ混晶 作成之半導體層之ρη接合型二極體能得出呈現正常整 流特性，高耐壓之二極體。從利用由本發明之ΒΡ作成 之半導體層或由ΒΡ系混晶作成之半導體層之LED，能 獲得高發光強度之藍色發光元件。另外，從利用由本發 明之BP作成之半導體層或由BP系混晶作成之半導體層 之受光元件，能得出空轉電流特性優之近紫外線領域用 之受光元件。 另外從使用由本發明之B P作成之半導體層或由B P 系混晶作成之半導體層之TEGFET能獲得能顯現高電子 移動度之電場效果型電晶體。另外，從使用由本發明之 BP作成之半導體層或由BP系混晶作成之半導體層之 HBT能得出直流放大率高，且安定之HBT。再者，從使 -50- 559899 五、發明說明（49) 用由本發明之BP作成之半導體層或由BP系混晶作成$ 半導體層之赫爾（hall)元件，能得出耐熱性優之高靈敏 度之赫爾元件。 依本發明之寬廣帶隙之BP或BP系混晶層之形成方 法，具有能安定地形成室溫時爲2.8eV以上3.4eV以下 以往沒有之範圍內之高帶隙之磷化硼（B P )或B P系混晶 之效果。因此之故，能實現與其它半導體形成各種異類 接合構造體。例如，從具有本發明範圍之帶隙之BP， 得出能構成對磷氮化鎵（GaNP混晶）施予障壁作用之異類 接合構造之效果，這從帶隙爲2eV之以往BP是無法得 到的。 另外，依本發明之BP或BP系混晶層之形成方法， 即使由具有晶格不匹配關係之單結晶做爲基板材料而得 出化合物半導體所需之積層構造體之情形，也能由能緩 和基板材料和積層構造體之構成層之不匹配性之B P或 B P系混晶構成緩衝層，更甚者，在能緩和晶格不匹配 之緩衝層上能形成結晶性優之BP層或BP混晶層。因 此，依本發明之形成方法，能形成結晶性優之BP或BP 系混晶層之積層構造體，進而具有能提供特性優之化合 物半導體元件之效果。 (圖面之簡單說明） 第1圖係爲III-V族化合物半導體之室溫時之帶隙和 構成元件之平均原子序號之相關圖。 -51 - 559899 五、發明說明（5〇) 第2圖係爲示出本發明之BP半導體層之吸收係數之 光子能量依存性。 第3圖係爲本發明有關之B P半導體層之陰極冷光 (cathode luminescence)之光譜 ° 第4圖係爲利用本發明有關之BP半導體層構成之 TEGFET之斷面模式圖。 第5圖係利用本發明有關之BP半導體層構成之赫爾 元件用途之積層構造體之模式斷面圖。 第6圖係爲本發明之實施例1有關之pn接合型LED 之斷面模式圖。 第7圖係爲示出本發明之實施例1有關之B P層之折 射率和消衰係數之波長依存性之圖。 第8圖係爲本發明實施例1有關之BP層之介電係數 之虛數部和光子能量之關係圖。 第9圖係爲本發明實施例2有關之pn接合型二極體 之斷面模式圖。 第1 〇圖係爲示出本發明實施例2有關之pn接合型二 極體之電流-電壓特性之圖。 第1 1圖係爲示出本發明實施例3有關nPn接合型 HBT之斷面構造之模式圖。 第1 2圖係爲本發明實施例4有關之受光元件之斷面 模式圖。 -52- 559899 五、發明說明（51) (符號說明） 1 0 : Η B T 101 :η形Si單結晶基板 1 0 3 :集極層 1 〇 5 :中間層 1 0 7 :射極層 1 0 9 :射極層 1 1 1 :基極電極 21:受光元件用積層構造體 202:BP低溫緩衝層 204:肖特基電極 40:二維電子短效型電晶體 4 0 2 :低溫結晶層 404:電子行走層 406:電子供給層 4 0 8 :閘極電極 4 1 0 :洩極電極 5 〇 1 :基板 5 0 3 :第2緩衝層 5 0 5 :間隔層 60 ： LED 601 :基板 6 0 3 :下部障壁層 6 0 5 :上部障壁層 6 0 7 :電流擴散層 6 0 9 : p形歐姆電極 901 :基板 902- 1 :低溫結晶層 9 0 3 : η 形 B P 層 9 0 5 : ρ形歐姆電極 11:ΗΒΤ用積層構造體 102:低溫緩衝層 104 •.副集極層 1 0 6 :基極層 1 0 8 :接觸層 1 1 〇 :集極電極 20:受光元件 201:藍寶石基板 2 0 3 : Β Ρ主動層 2 0 5 :歐姆電極 401 :基板 403:高溫結晶層 4 0 5 :間隔層 4 0 7 :接觸層 4 0 9 :源極電極 4 1 1 :凹部 5 02:第1緩衝層 5 0 4 ·.磁感層 6 1·· LED用途積層構造體 602:低溫緩衝層 604:發光層 606:發光部 608:n形歐姆電極 9 0 :二極體 9 0 2 :緩衝層 9 0 2 - 2 :局溫結晶層 904:p 形 BP 層 9 0 6 : η形歐姆電極 -53--18- 559899 5. Description of the invention (17) The electron supply layer of TEGFET, for example, uses a layer thickness of about 10 nm to about 5 nm, and a carrier concentrate of about 1 X 1 〇18 cm -3 to about 5 X 1 〇 18 cm-3 η-shaped PB layer and so on. A light-emitting diode (LED) is used to efficiently lead light out of the outside. The window layer is a conductive shape of the base layer corresponding to the cover layer, etc., which is η-shaped or p-shaped, exceeding, for example, about 1 It is composed of BP or BP mixed crystal layer with good conductivity of x 丨 〇18 cm-3. In addition, the laser diode (LD), the current narrow layer is composed of a conductive layer opposite to the base layer of the upper cover layer and the like, or a BP or BP mixed crystal layer with high resistance. . Boron phosphide (BP) two-dimensional semiconductors are indirect transfer semiconductors (see "Semiconductor Device Theory" above, page 28). In contrast, the ionic binding property of Philips of BP is as small as 0.006 (refer to the above-mentioned "Semiconductor Bond Theory", pages 49 to 51). Therefore, the electrical activation rate of the dopant is high, and it is easy to obtain a low-resistance BP crystal layer with a high carrier concentration. The present invention makes good use of such a low-resistance BP layer, for example, a current diffusion layer of an LED and an ohmic contact layer of an LD or FET to form a BP-based semiconductor element. In addition, a BP-based semiconductor device that requires a conductive buffer layer, and such a low-resistance BP layer can be suitably used to form a conductive buffer layer. The BP crystal layer and the BP-based mixed crystal layer according to the present invention use, for example, the well-known organic metal chemical vapor deposition (MOCVD) method (see Inst. Phys. Conf. Ser.? N ο. 1 2 9 (IOP 5 Pub 1 ishing Ltd., 1 9 93), pages 157 ~ 162), molecular wire crystal film (MB E) method (see -19-559899 V. Description of the invention (18) J. Solid State Chem 133 (1997 ), Pages 269 to 272), and grow by a vapor phase growth method such as a halide method or a hydride method. The organometallic vapor deposition method is a vapor growth method using an organic compound of boron (B) as a source of boron (B). MOCVD method, for example, boron phosphide · gallium (BxGai_xP: 0 $ X $ l) mixed crystal system uses diethyl ((C2D3B), trimethylgallium ((CH3) 3Ga), or triethylgallium ( (C2H5) 3Ga), phosphine (PH3) or trihydroxy (Ui alkyl) phosphorus and other organic compounds made of organic materials and grow. Halogen (halide) of the crystalline layer of boron phosphide (BP) vapor phase To grow, for example, a halide of boron (B) such as boron trichloride (BC13) can be used as the source of boron (B), and a halide of phosphorus such as phosphorus trichloride (PC13) can be used as phosphorus ( P) Source (refer to "Journal of the Japan Society for Crystal Growth"), Vo 1.24, No. 2 (1 997), p. 150). In addition, there is also a halide method using boron trichloride (BC13) as a source of boron (B) (refer to Appl. 1 "5., 42 (1) (1 97 1), pp. 420 ~ 424). Hydride (1 ^ (11 heart (1) method is 'for example' using borane (BH3) or diborane (B2H6), etc. as a source of boron (B), using phosphine (PH3), etc. As a source of phosphorus (P), the BP crystal layer can be grown. (Refer to (1) J. Crystal Growth, 24/25 (1974), pages 193 to 196, and (2) J. Crystal Growth, 1 3 2 ( 1 9 93), pp. 611 ~ 613). According to the vapor phase growth method, for example, compared to the conventional method of cultivating phosphorus from a nickel (Ni) -phosphorus (P) melt or copper (Cu) -phosphorus (P) melt. The so-called liquid phase growth method of boron (BP) crystals (refer to J · E 1 ec 11. 〇chem. S 〇c., 1 2 0 (6) (1 9 7 3), 8 0 2 to 8 0 6 Page) 'It has simple and easy to control the layer of β P-based mixed crystal layer-20-559899 V. Description of the invention (19) The advantage of thick and mixed crystal composition ratio. In addition, according to the vapor phase growth method, it also has a BP layer or BP-based mixed crystal layers can easily form heterojunction structures with other semiconductor crystal layers Advantages. Especially according to the MOCVD method, which can instantly change the piping system of the gas source material to be supplied to the growth reactor, the composition of the crystal layer can be changed rapidly. The so-called jitter that changes the composition rapidly by borrowing a Hetero joint interface The heterogeneous joint interface structure can efficiently accumulate low-dimensional electrons. Therefore, the heterogeneous joint interface structure that is shaken with the BP layer or the BP-based mixed crystal layer formed by the MOCVD method has, for example, a method that achieves excellent electron mobility BF of TEGFET and other semiconductor elements. The temperature required to grow the BP layer or BP mixed crystal layer depends on the vapor phase growth method and the crystal form of the substrate as the crystalline material and the BP layer or BP mixed crystal layer of the target object. However, to obtain a single-crystal BP layer, it has almost nothing to do with some of the above-mentioned vapor phase growth methods, which requires a high temperature of more than .750 ° C. To use triethylboron ((C2H5) 3B) / phosphine (PH3) / hydrogen (112) reaction system at atmospheric pressure (approximately atmospheric pressure) or reduced pressure MOCVD method to obtain a single crystal BP layer, the appropriate temperature is 75 0 ° C above 1200 ° C to F (refer to the United States Patent US-6,0 69,02 1 No.) In other words, the substrate material must be selected from crystals that have heat resistance that will not deteriorate at such high temperatures. The substrate materials that have heat resistance in this high temperature area include boron phosphide (BP) single crystals (see ( 1) Z. anorg · allg · Chem ·, 349 (1967), (2) Kristall und Technik, 2 (4) (1967), pages 523 to 534, (3) Kristall und technik, 4 (4) 1 969), 4 8 7 ~ 493), and (4) above -21-559899 V. J. Electro Chem. Soc. 120 (1973) described in the description of the invention (20). Examples of sapphire (α-Α12〇3), silicon carbide (SiC) (refer to J. Appl Phys., 42 (l) (197 1) above, and silicon (silicon single crystal). High temperature exceeding 1200 ° C, The bulk of boron phosphide described by the molecular formulas B6P and B13P2 becomes easy to form (refer to J. Am Ceram. Soc., 47 (l) (1964), pages 44 ~ 46). However, it is not conducive to obtaining a single body A single crystal layer made of boron phosphide (b οr ο nm ο η 〇ph 〇sphide). Can be formed from a single crystal BP layer or a BP mixed crystal layer, for example, an electron supply layer of a TEGFET. In addition, it can constitute The barrier layer of LED or LD. The crystal form (structure) of the growing BP layer or its mixed crystal layer is generally a diffraction pattern (diffraction pattern η) generated by X-ray diffraction (XRD) and electron diffraction. ). The spot-like diffraction points are caused by single crystals (see J. Crystal Growth, 70 (1 984), pages 5 07 to 514). In addition, according to the MOCVD method of the same reaction system To obtain a heterogeneous or polycrystalline BP crystal layer, the appropriate temperature is a lower temperature of 250 ° C ~ 75 ° C (see Said US-6,069,021 is a BP layer or a BP-based mixed crystal layer made of amorphous (am 〇rph 〇us) as the main body. When the BP layer or the BP mixed crystal layer formed on the substrate is mismatched, In the case of a multilayer structure of a phosphorous semiconductor device used for a growth layer, it has the effect of mitigating lattice mismatch, thereby achieving a growth layer with excellent crystallinity. In addition, it effectively prevents the substrate material and The difference in thermal expansion coefficient of the growth layer causes the growth layer to be peeled from the substrate surface. Therefore, for example, amorphous -22- 559899 is used as the main component. The BP layer of the body of the invention (21) can be used as a phosphorus system. Buffer layer for semiconductor devices. In addition, the buffer layer can also be made of, for example, a single crystal layer of boron phosphide (BP) grown at a higher temperature on an amorphous boron phosphide layer grown at a lower temperature. Structure (refer to the above-mentioned US Patent No. 6,0 2 9, 0 2 1). Even when using a substrate with a mismatch relationship with BP on the lattice, as long as there is an amorphous substrate interposed therebetween BP can A BP single crystal layer with excellent crystallinity is easily obtained. For example, a boron phosphide-based semiconductor light-emitting device has the advantage of forming a light-emitting portion that obtains high-intensity light emission on a buffer layer made of a self-laminated structure. In addition, for example, phosphating Boron-based HBT can help to obtain a good collector layer or 畐 丨 J collector (sub--) with few crystal defects such as misfit transitions caused by lattice mismatch on the buffer layer of the multilayer structure. collector) 〇 From the BP-based mixed crystal layer, a growth layer that can be lattice-matched to a single crystal substrate can be formed. For example, a boron phosphide-gallium mixed crystal (Bo. ^ Gao 98P) with a boron composition ratio of 0.02 (boron phosphide mixed crystal ratio = 2%) (refer to Japanese Patent Application Laid-Open No. 1 1-266006) is A BP-based mixed crystal layer with a lattice constant of 5.43 09A. Therefore, from Bo.c2Gao.98P (refer to the aforementioned Japanese Patent Application Laid-Open No. 1 1-26 600 6), a growth layer matching the lattice of Si single crystal (lattice constant = 5.4 3 0 9 A) and The Si single crystal lattice matching growth layer used as the substrate can also be composed of BP mixed crystal ratio of 33% boron indium phosphide mixed crystal (BG.33In〇.67P). It can be composed of a PB mixed crystal growth layer that matches the lattice of the substrate, for example, a good buffer. In addition, it is possible to construct a magnetic induction layer exhibiting a Hall element suitable for obtaining a high product sensitivity. -23- 559899 5. Invention Description (22). In addition, it can be suitably used for a light transmitting layer (window layer) of a light receiving element. The semiconductor device provided with a semiconductor made of boron phosphide (BP) of the present invention is composed of a semiconductor layer having boron phosphide (BP) having a band gap at room temperature of 2.8 electron volts (eV) or more and 3.4 eV or less. In addition, a semiconductor device including a semiconductor layer made of a boron phosphide (BP) -based mixed crystal of the present invention is a BP-based mixed crystal composed of a BP having a band gap of 2.8 electron volts (eV) or more and 3.4 eV or less at room temperature. Semiconductor layer. The room temperature is about 20 ° C. That is, the BP or BP mixed crystal layer with an intermediate band gap previously unknown is used to form a BP-based semiconductor, using a band gap larger than 2eV of the conventional BP, but not as high as 4.2eV to 6.0eV reported in the past. element. A boron phosphide (BP) layer with a band gap of 2.8 e V to 3.4 e V at room temperature can be formed by specifying its growth conditions. In particular, it can be formed by setting both the growth rate and the supply ratio of raw materials to a predetermined range. The growth rate of the boron phosphide (BP) layer or the BP-based mixed crystal layer is well between 20A and 300A per minute. If the growth rate is a slow rate of 20 A / min or less, the phosphorus (P) constituent element or its compound cannot be sufficiently inhibited from detaching from the surface of the growth layer and volatilizing. As a result, film formation may not be achieved. If it is set to exceed a rapid growth rate of 300 A / m i η, the band gap obtained is unstable and unsatisfactory. In addition, if the growth rate is increased in vain, the polycrystalline crystal layer tends to be generated, which is not good for obtaining a single crystal layer. In addition, in accordance with the growth rate, the supply ratio of good raw materials is specified. -24- 559899 V. Description of the invention (23) The range is 15 or more and 60 or less. In the case of forming the BP layer, the supply ratio of the raw material means the ratio of the supply amount of the phosphorus (P) source to the growth reaction system and the supply amount of the boron source. In addition, if it is a case where a BP-based mixed crystal is formed, it means the ratio of the total supply amount of the Group V element source containing scale (P) to the total supply of the Group 111 element source containing Boron (B). Taking the formation of boron phosphide · indium (BxInuPiO ^ XSl) mixed crystal as an example, it means that for the growth reaction system, the supply amount of phosphorus (P) source is the total amount of boron (B) source and indium (In) source. ratio. That is, it is a so-called V / III ratio. If the V / III ratio is less than 15, the surface of the growth layer may cause unwanted clutter. On the contrary, if the ratio of π / ν exceeds 60, it is easy to form a phosphorus-rich (P) growth layer from the perspective of stoichiometric theory. Excessive phosphorus (P) enters the position where boron (B) should occupy on the crystal lattice, and becomes a donor (refer to "The 100th Collection of Semiconductor Technology in the Ultra LSI Era [5]" by Ohno Shono (Ohm Issued by the company (company) on May 1, Showa 59, Electronic Journal Electronic Volume 29 No. 5 (May, Showa 59) Addendum, page 1 21). BP or BP is a type of mixed crystal The sphalerite crystal originally had a valence electron band structure that can easily obtain the narrow band gap of the P-shaped semiconductor layer (refer to Ikuko Toshiaki and Ikuko Toyoaki co-authored "Basic Introduction to Compound Semiconductors", issued by Peifeng Pavilion (Company) September 10, 1991 (First edition, pages 14-17). Nevertheless, the stoichiometric composition tends to form phosphorus-rich (P), which leads to problems that prevent the formation of low-resistance P-shaped crystal layers. Review the past gas phase growth The formation conditions of the BP layer on the method, diborane (B 2 Η 6) / phosphine (P Η 3) / hydrogen (Η 2) series hydride method, there are descriptions of growth -25- 559899 V. Description of the invention (24 ) When the speed is about 120A / min ~ 70A / min (refer to the above Jpn. J. Appl, Phys., 1 3 (1 974)). In addition, the hydride growth method indicates that the V / III ratio (= PH3 / B2H6) must be about 50 or more to grow the BP layer (refer to Jpn J. Appl above). Phys., 1 3 (1 974). In particular, it is stated that in order to obtain a single crystal BP layer, the V / III ratio must be increased to 25 0 (refer to Jpn · J. Appl. Phys., 1 3 (1 974 above). )). In other cases where diborane and phosphine are used as the raw materials to form the BP layer, the minimum growth rate must be set to 400 A / min (see "Semiconductor Technology (Part 1)" by Kemono Shono. Consortium) 9th printing issued on June 25, 992), pages 74 to 77). To obtain a BP layer that exhibits semiconductor properties, V / III must be 100 times or more (refer to the above-mentioned "Semiconductor Technology (I)" ", Pages 76 to 77). Therefore, the conventional B2H6 / PH3 / H2 hydride method has not reached the low growth rate mentioned in the present invention, and the V / III ratio satisfies the specified range of the present invention. In the halide method using chloride as a raw material, although the V / III ratio is set to satisfy the scope of the present invention, it is used as a halide of the raw material. During vapor phase growth, the BP layer or Si layer plate itself is eroded due to the halide generated by decomposition, which causes the problem that it is difficult to obtain a BP layer with a flat surface. At the same time, the growth rate and V / Under the conditions of both III ratios, it is appropriate to grow the BP layer or the BP-based mixed crystal layer by the M CVD method. In particular, the MOCVD method using a triborate (t r a a 1 ky 1 boron) compound as a source of boron (B) (see inst. Phys. Conf. Ser., No. l29 above) can be used well. Among trihydroxy boron compounds, especially -26- 559899 V. Description of the invention (25) MOCVD method using triethylboron ((C2H03B) can easily perform an amorphous BP layer at a low temperature, or The formation of BP-based mixed crystal layer, and the formation of single crystal layer can also be performed at high temperature. Trimethylboron ((H3) 3B) is the same as the boron and diborane at room temperature, and it should be a low temperature. The formation of a BP layer or a BP crystal layer is not as suitable as trimethyl boron. To form a BP layer or a BP crystal layer at a low temperature is suitable as a boron (B) source is a boiling point M 'organic liquid at normal temperature Boron compounds. For example, when a triethylboron / phosphine / hydrogen MOCVD reaction system is used to form a single crystal layer of boron phosphide (BP), the growth temperature is 85 (TC above 1150. (: Below. More preferably, the system 90 ° C or higher and 1100 ° C or lower. A good temperature is 95 ° T: ~ 105 ° t. For example, when the V / III ratio is set to 30 at 950 ° C, it is stable. A single crystal layer of boron phosphide (BP) with a band gap of 2.9 eV is obtained. The band gap (= Eg) is, for example, from the general photo luminescen ce: PL) method, cathode cold light (cathode 1 uminescence: CL), or the relationship between absorption coefficient and photon (phot ο η) energy (refer to Zeager's "Physics of Semiconductors (Part 2)" above, pp. 390 ~ 450 Figure 2 shows the photon energy of an un-dope BP layer on the surface of a Si single crystal substrate having a P-shaped (1 Π) plane with boron (B) added under the above conditions. The dependence of the absorption coefficient (absorption c (Efficient). The band gap at room temperature obtained from the relationship between the self-absorption coefficient (a: cm 1 and photon energy (hv: eV) is about 3. leV. That is, related For BP crystals, the rate of change (temperature coefficient) of the band gap according to temperature is known to be negative (-) 4.5x1 0_4eV per unit of absolute temperature (refer to the above-mentioned Z. -27- 559899. V. Description of the invention (26) anorg. Allg. Chem., 3 49 (l 967)). The negative sign of this temperature coefficient means the lower the temperature, the higher the band gap. Therefore, for example, the band gap system of the BP layer at the temperature of liquid nitrogen (= 77K) It is about 3.2 eV. In this way, the growth rate and V / III ratio can be made within the scope of the present invention, and the present invention can be obtained. BP layer. In addition, FIG. 3 shows magnesium (Mg) grown by using the same MOCVD reaction system as above, and the growth rate and the V / III ratio were set to 100A / min and 60 at a temperature of 95 ° C. An example of the CL spectrum of a doped P-shaped boron phosphide (BP) layer. This spectrum is measured at a temperature of 30K. Boron phosphide (BP) is an indirect migration semiconductor, so CL spectrum is suitable for obtaining at 77K or lower. The carrier concentration of the P-shaped BP layer used as the sample was about 8 × 1018 αιΤ3. In addition, the layer thickness is about 2.2 // m. The components of the CL spectrum shown in Figure 3, if analyzed by a general peak separation method, are spectra with a peak wavelength of about 3 78 5A (shown by the symbol "SP 1" in Figure 3), and The spectrum of the peak wavelength is about 5696A (indicated by the symbol "SP2"). "SP2" can be speculated to be caused by the "deep" impurity level. In addition, the characteristic of the spectrum shown by "SP2" is that the emission intensity is confirmed to decrease with time. On the other hand, "SP 1" is a spectrum estimated to be a band-end absorption, and a band gap of about 3.2 eV can be calculated from its peak wavelength (3 7 8 5 A). For example, an undoped boron phosphide (BP) layer grown by the MOCVD method of triethylboron ((C2H5) 3B) / phosphine (PH3) / hydrogen (H2) is used as an example. Generally, an amorphous layer has High band gap. In particular, for example, at room temperature, the band gap of a BP amorphous layer containing distortion caused by the lattice mismatch with the base layer of -28- 559899 V. Invention description (27) generally becomes 3.0 e V To 3.4 e V. Generally, the band gap of a BP polycrystalline layer grown by increasing the growth rate tends to become smaller. In particular, for a film having a layer thickness greater than about 2 to 3 "m, the band gap may be reduced to about 2.8 eV to 3.0 eV. In addition, a single layer grown under the conditions of a growth rate and a V / III ratio in the appropriate range described above The crystalline BP layer can obtain the intermediate band gap between the amorphous layer and the polycrystalline layer. By using the boron phosphide (BP) having the band gap of the present invention, it is possible to form a band gap that has never existed, and generally BaAlpGaym α_β_γP §AseN 1 _δ-ε (〇 < α £ ΐ), 0 < β < 1 »0 < γ < 1 »0 < (χ + β + γ = 1, 〇 < δ < 1 > 0 < ε < 1 »〇 $ δ + ε ^ 1) described in the PB-based mixed crystal. For example, by using boron phosphide (BP) of the present invention with a band gap of 2.8eV or more and 3-4eV or less, a phosphorous boron arsenide mixed crystal with a band gap of 1.5eV or more and 3.4eV or less at room temperature (B δδA5ε: 0 < δ < 1 ’〇 < ε < 1 'δ + ε = 1). Using conventional BP crystals with a band gap of about 2.0 eV, only a band gap with boron arsenide (B as) of about 1.5 eV or more can be formed (refer to the above-mentioned "II__group compound semiconductor", page 150), phosphorus B P δ A s mixed crystal with a narrow band gap of about 2.0 eV (Bp) < δ < 1,0 < ε < 1, δ + ε = 1). In addition, the use of boron phosphide (BP) related to the present invention with a band gap of 2.8eV to 3.4eV can form a boron phosphide-gallium mixed crystal (BxGa ^) with a band gap of 2.3eV to 3.4eV at room temperature. xP: 0 < X < 1). Because the band gap of gallium phosphide (GaP) at room temperature is 2 · 3 e V (refer to the "Semiconductor Theory" above, page 28), if the crystal is mixed with boron phosphide (BP) to Increasing the mixed crystal ratio of BP-29- 559899 5. In the description of the invention (28), that is, by increasing the composition ratio (= X) of boron (B), a mixed crystal of (BxGanPiiXXcl) with a content of 2.3 eV or more can be formed. However, the BxGauPWKl) mixed crystal formed by the conventional BP with a band gap of 2.0eV can only form a BxGa ^ xPacXd) mixed crystal with a narrow band gap of about 2.0eV to 2.3eV. Such as B X G a 1 _ X P (0 < X < 1) The mixed crystal has the advantage that a BP-based mixed crystal that does not contain arsenic as a constituent element can constitute a boron phosphide-based semiconductor device that has been considered to prevent pollution to the environment. The BP-based mixed crystal composed of the BP crystal of the present invention having a band gap of 2.8 eV or more and 3.4 eV or less, as in the above-mentioned example, has a wide range not found in conventional BP-based mixed crystals and has a high band gap. For this reason, for example, it is particularly useful in forming a barrier layer for a light-emitting layer provided to emit short-wavelength light. For example, a Bο.μΑΙο.μP mixed crystal with a boron composition ratio (= X) of 0.90 can be used for a light-emitting layer made of a gallium nitride-indium mixed crystal (Ga.75In (). 25N) of a cubic crystal. Form the barrier layer. In addition, boron phosphide (BP) or BP-based mixed crystal systems are sphalerite-type crystals, and are in a band structure that can be easily obtained from their valence electron bands (refer to the "Basic Introduction to Compound Semiconductors" above) to obtain P The shape of the layer. Therefore, for example, unlike a hexahedral gallium nitride (h-GaN), a barrier layer of a P-shape and a low resistance can be easily formed. Near-ultraviolet light with a blue-violet emission wavelength of 443 0A is emitted from the light-emitting layer of GamInmN in the façade crystal. The heterojunction structure has the advantage of a single or double heterojunction structure with a blue band emitting pn junction type light emitting portion. Even more -30- 559899 V. Description of the invention (29). The mixed crystal systems of BG.9GA1 (). 1 () P and Ga.75In (). 25N have the same lattice constant (= 4.62 8 A) (The lattice constant of the indium nitride (InN) of the cubic crystal is calculated at 4.98 A: refer to the above-mentioned "Group 111-V compound semiconductor", page 330). In other words, since the BP mixed crystal of the present invention can form a barrier layer matching the row lattice of the light-emitting layer, it can constitute a light-emitting portion of the lattice matching system. The crystalline layer having a mutual lattice matching relationship becomes a good crystalline layer with few crystal defects caused by the lattice matching. For this reason, high-intensity light emission is emitted from the light-emitting part of the lattice matching system one by one, which is further helpful for realizing a boron phosphide-based semiconductor light-emitting device with high brightness. Furthermore, a crystalline layer having a mutual lattice matching relationship means a crystalline layer having a relationship in which the degree of lattice mismatch is within ± 0.4%. In addition, by using the boron phosphide (BP) layer or the BP-based mixed crystal layer of the present invention, a light-emitting portion suitable for constituting a lattice matching system of LED or LD can be conveniently constructed. For example, the composition ratio of the barrier layer made of η-formed p-shaped boron phosphide (BP: lattice constant: 4.5 3 8 A) and self-phosphorus (P) is 0.03 phosphorous gallium nitride (GaNQ.97P (). H: Lattice constant = 4.5 3 8 A) Mixed light-emitting layers can form a lattice-matching system, for example, a pn-junction light-emitting portion. In addition, from a planar crystal with a disk composition ratio of 0.10 / < £ G a N 〇9 ο Ρ ο 1 () Create a Z light emitting layer and a barrier layer made of boron phosphide · gallium (B0.93Ga0.07P) with a gallium (Ga) composition ratio of 0.07. , Can easily constitute the light-emitting part of the lattice matching system. Similarly, using a gallium nitride arsenide (GaNuAsxiOSXy) as a light-emitting layer can also form a lattice-matching light-emitting portion. However, compared to the growth energy of gallium nitride (GaN) under standard conditions (-) 26.2Kcal / -31-559899 V. Description of the invention (30) mol, the growth energy of GaAs is (-) 19.2 kcal / mol. (Refer to Japanese Patent Application Publication No. Hei 10-3483487). On the other hand, the growth energy of GaP is smaller than (-) 29.2 kcal / mol, and the growth energy of GaN is smaller (refer to the aforementioned Japanese Patent Application Publication No. Hei 10-53487). For this reason, compared to the GaNi.xASx mixed crystal, the GaNuPx mixed crystal can be formed easily and easily. The barrier layer, compared to the GaN, _XPX light-emitting layer, is composed of a BP layer or a BP-based mixed crystal layer with a larger band gap at room temperature. From about (KleV or more, preferably 0.3 eV or more, a high band gap BP layer or a BP-based mixed crystal layer can constitute a barrier layer functioning sufficiently as a barrier layer of the light emitting layer. In addition, the boron phosphide of the present invention ( BP) or BP-based mixed crystals, as described above, have a band gap that can transmit visible light of short wavelengths. Therefore, for example, adjusting the boron composition ratio (= X) to obtain BxGai_xP with a band gap of 2.7eV or more (Using BP crystal with a band gap of 3.0eV at room temperature is 0.4 ^ × < 1) An LED light-emitting transmission layer (wavelength) having a transmittance with a wavelength of approximately 4 5 90 A long can be formed well. In addition, from boron phosphide-indium (BχΙηι-χΡ) mixed crystals with a band gap in the range of 2.8eV to 3.4eV, it can be used as a light-emitting LED or surface-emitting LD with a wavelength longer than approximately 4430 Α (see Iga and Koyama co-authored "Area Luminescence Laser" (Ohm (Company), issued September 25, 990, first edition, first print), pages 4-5). In addition, it can be used as a reflector for LED or surface emitting laser applications (refer to the above-mentioned "surface emitting laser", pages 118 to 119). -32- 559899 V. Description of the invention (31) A laminated structure composed of a GaNi_XPX mixed crystal and a BP layer or a BP-based mixed crystal of the present invention, which can be easily grown, can constitute a light-receiving portion for a light-receiving element. For example, a bonded structure of boron phosphide (BP) or BP-based mixed crystal layer and a semiconductor layer having a lattice mismatch with these layers of 0.4% or less can constitute a signal / noise intensity ratio, that is, a large S / N ratio , Light-receiving section for light-receiving element applications with excellent light-receiving sensitivity. In particular, for example, a boron phosphide (BP) layer and a semiconductor layer that matches the lattice of this layer, for example, a light-receiving portion made of a structure that is heterogeneously bonded to the above-mentioned GaN ^ Px layer can constitute an idling current. (Id 1 ingcur 1 · ent) A light-receiving part for a high-sensitivity light-receiving element with a low light-receiving property. In addition, the BP layer or the BP-based mixed crystal layer of the present invention is useful as a light-transmitting layer capable of efficiently introducing a light-measuring object into a light-receiving layer. In particular, short-wavelength visible light such as a BP layer or a BP-based mixed crystal layer having a relatively high range band gap of 2.8eV or more, which is not available in the past, can be efficiently transmitted even with blue light, and therefore, it can be effectively used for Short-wavelength visible light is used as the window layer of the light-receiving element of the photometric object. A heterojunction structure made of a boron phosphide (BP) layer or a BP-based mixed crystal layer and a semiconductor layer matching the lattice of these layers has the advantage of enabling carriers, such as electrons, to be transported at high speed. For example, a BP layer or a BP mixed crystal layer and a heterojunction bonding structure system of GaN ^ Px mixed crystal are suitable for forming a functional layer of a TEGFET that requires high-speed mobility of electrons. A direct migration G aN i _ XPX mixed Since the crystal layer can exhibit high electron mobility, it is particularly suitable for an electrical f-walking layer constituting a TEGFET. In addition, the BP layer or the BP-based mixed crystal layer can be composed with the electron walking layer -33- 559899 V. Description of the invention (32) Heterogeneous bonding 'to constitute an electron supply layer that obtains the function of supplying electrons in the electron walking layer. In addition, the B P layer or the B P-based mixed crystal layer of the present invention can also constitute a spacer layer disposed between the electron supply layer and the electron walking layer. The band gap of the electron supply layer or the spacer layer is preferably about 0.2 eV or more, and more preferably about 0.3 eV or more than the constituent material of the electron walking layer. According to the general formula BaAlpGaylm.a.piPsASeNne (0 < α < 150 < β < 1 »0 < γ < 1 »0 < α + β + γ < 1 »〇 < δ < 1,0 < ε < 1, 0 < δ + ε $ 1). In particular, a GaN 丨 _χ Pχ mixed crystal layer is easier to form than an arsenide for the reasons described above. In addition, if the band gap bowing based on the composition ratio of phosphorous (P) of GaNuPx mixed crystal is used (see Appl Phys Lett., 60 (20) (1992), pages 2540 ~ 2 542), change by Composition of phosphorus (p) in the field of direct migration ° /. Degree, can change the band gap. For example, if the composition ratio of phosphorus (P) is 5 ° /. It can reduce the band gap from 3.2 ^ to about 2.86 ¥. That is, it has a simple composition from GaN ^ Px mixed crystals and can correspond to the composition ratio of phosphorus (P). The band gap from the spacer layer or electron supply layer made of the BP layer or BP-based mixed crystal layer is good as described above. Advantages of the band-gap electron walking layer. For example, as shown in the pattern example in Fig. 4, on a substrate 401 made of sapphire with a plane orientation of (000 1) (C plane), for example, 2.8 eV or more in accordance with (1), 3.4 In the range below eV, it is well above 3eV, and the band gap layer thickness (= d) is about 100A of undoped high resistance boron phosphide. Ming (8 \ 人 11 _) ^: 〇 < 乂 < 1) The low temperature of the amorphous body as the main body is slow-34- 5. Explanation of the invention (33) The punched layer 402, (2) It is formed at a higher temperature than the low-temperature buffer layer 402, and the band gap is 3eV Above, for example, the carrier concentration (= n) is less than 5xl015 cm, and d = 3 00A. The high-temperature buffer layer 403 is made of undoped n-shaped BP. (3) The BP line formed with the high-temperature buffer layer 403 is formed. Lattice matching and smaller band gap, for example, polyhedral undoped η-shaped GaNa. ^ Po.od (for example, n = 5xl016 cm _3, d = 2 5〇A) constitutes an electron walking layer 404, (4) Spacer layer made of a doped η-shaped BP with a good band gap of 3eV or more and a band gap higher than the electron walking layer 104, for example, a carrier concentration (= n) of less than 5xl015 cnT3, and d = 5 0 A 4 0 5, (5) It is made of doped n-shaped BP of silicon (Si) with a good band gap of 3eV or more, for example, the carrier concentration (= n) is less than 2xl018 cn plant 3, d = 25〇A. The electron supply layer 406, (6) has a good band gap below the electron supply layer 406. For example, the carrier concentration (= n) is about 5 × 1018 cnT3, and d = 150A is doped with silicon (Si). Shape B The ohmic electrode contact layer 407 made of P is stacked in order to form a laminated structure 41 for TEGFET 40 use. Next, a recess (rece c s s) is applied to a part of the contact layer 407, and a Schottky junction gate electrode 408 is provided in the recess. In addition, on the surfaces of the contact layers 4 07 remaining on both sides of the recess 41 1, an ohmic source electrode 409 and a drain electrode 410 are formed on the surface of the contact layer 407 to form a TEGFET 40. -35- 559899 V. Description of the Invention (34) In addition, the GaNuPx mixed crystal layer can be used as a magnetic induction part of a Hall element by laminating it on boron phosphide (BP) or BP mixed crystal. In particular, the direct migration type and the non-indirect migration type, for example, a GaNu Pχ mixed crystal layer can be used as a magnetic induction layer (magnetic induction layer) of a Hull element. Furthermore, the GaN and χ P X mixed crystal layer can be made of indium antimonide (InSb, band gap = 0.18eV) or indium arsenide (InAs, band gap = 0.3 6eV) or gallium arsenide (GaAs, band gap = 1.43eVH £) (for the band gap at room temperature, refer to the "Group III-V compound semiconductor" above, page 150), the phosphorus composition ratio is both Large band gap (refer to Appl. Phys Lett., 60 (19 92) above). For semiconductor materials with a large band gap, the temperature at which the conductive material reaches the conductivity becomes higher (refer to the above-mentioned "Semiconductor Physics (Part 1) ", pages 5 to 10). Therefore, it is beneficial to construct a Hull element that can operate at high temperatures. By using a band gap higher than that of GaN 1.X Asx mixed crystals, such as GaN ^ xPx Mixed crystals can form a magnetic induction layer of an element that can operate at higher temperatures. Therefore, a heterogeneous junction structure formed from a GaN ^ Px mixed crystal layer and a BP layer or a BP-based mixed crystal layer has a structure capable of forming at high temperatures. Advantages of an environment-resistant Hull element that can also operate. In particular, a direct-migration type 11-shaped GaN that matches the lattice of the BP layer or BP-based mixed crystal layer. The 1-χρχ mixed crystal layer achieves higher electron mobility, therefore, it can help to obtain an environment-resistant Hull element with high sensitivity and capable of operating at high temperatures. The Hull elements related to the present invention are composed of It is composed of a plate and a laminated structure including, for example, a buffer layer and a magnetic induction layer. The cross-sectional view of Fig. 5 shows this -36-559899. V. Description of the invention (35) Use of environment-friendly Hull elements related to the invention An example of a laminated structure. The substrate 501 is made of, for example, a single crystal of silicon, sapphire, or silicon carbide (SiC). The first buffer layer 502 provided on the single crystal plate 501 is formed at a low temperature. It is grown, for example, made of amorphous n-shaped boron phosphide (BP). The second buffer layer 5 0 3 is grown at a higher temperature than the first buffer layer 5 02, for example, silicon (Si ) Doped η-shaped PB single crystal layer. The magnetic induction layer 504 is composed of boron phosphide (BP) (melting point: 3 000 ° C) (refer to "Semiconductor Device Theory" above, page 28) The same high melting point gallium nitride (G aN: Hexahedral crystal h-G aN melting point)> 1 700 ° C (refer to "Semiconductor Device Theory" above) Or gallium phosphorous nitride (GaN ^ xP ^ iXXci), etc. The magnetic induction layer 504 is preferably composed of a lattice mismatch with the base layer (if the multilayer structure shown in FIG. 5 is the second buffer layer 5 03). And it is composed of materials that match the lattice. The absolute value of the degree of lattice mismatch (△: the unit is the following formula is calculated from the lattice constant (= aQ) of the base layer and the lattice constant (= a) of the stacked layer. Δ ( %) = | (a- a〇) / a〇 | The lattice mismatch of GaN (a = 4.5l0A) and Β single crystal (a〇 = 4.5 3 8 A) in χ100 cubic body is only 0 · 6%, making it a suitable material for magnetic induction layers. In addition, in the as-grown state of the present configuration example, a buffer layer made of an amorphous material as the main body (Fig. 5, No. 1 to No. 5 02) has a function of alleviating lattice mismatch, and thus helps In order to improve the crystallinity of the upper layer. The lattice constant of the gallium phosphorous nitride (GaNuPo. 03) with a nitrogen composition ratio of 0.03 was the same as that of the BP single crystal, and was 4.5 3 8 A. From this line of lattices • 37- 559899 V. Description of the invention (36) The magnetic induction layer made of matched materials has a low density of crystal defects such as misfit transitions caused by lattice mismatches, and thus becomes good quality. Crystal layer. Therefore, it is possible to provide a high-sensitivity Hull element which is excellent in heat resistance by being highly mobile. For example, using triethylboron ((C2H5) 3B) / phosphine (PH3) / ammonia (NH3) / hydrogen (H2) is the atmospheric pressure MOCVD method, and the surface orientation is (100) phosphorus (P) doped η The following growth layers are sequentially stacked on the surface of the Si-shaped single crystal substrate 501. (1) A first buffer layer 502 made of an un-dope n-shaped BP layer having a layer thickness (= d) of about 70 A and a band gap of about 3.1 eV at room temperature. (2) A second buffer layer 5 0 3 (d = 0.7 // m) made of a η-shaped PB layer with a carrier concentration (= η) of about 6x1 〇15 αι3 and a band gap of about 3.0 eV at room temperature. . (3) Magnetic induction created by η-shaped GaNO.97Po.G3 of an orthorhombic crystal with d = 0.1 // m, n = 2xl016 cm, and mobility at room temperature of about 8 50 cm 2 / V * S Layer 504, and then mesa processing is performed on the magnetic induction layer 504 by means of plasma etching of methane (CH4) / argon (Ar) / hydrogen (Η2) system. Furthermore, an ohmic electrode made of, for example, gold (Au) or Au alloy is placed on the 4 ends of the magnetic induction layer 504 that has a cross shape remaining as a magnetic induction portion (Hall cross portion). Such a configuration can provide a high sensitivity Hull element with a product sensitivity (p r d u c t s en t s i t i v i t y) at room temperature of approximately 15 m V / m A · K G for environmental resistance. Since the boron phosphide (BP) of the present invention has a large band gap larger than the conventional band gap (approximately 2 eV), it is possible to form a BP-based mixed crystal having a large band gap not previously available from the BP of the invention. Therefore, when the band gap is different from -38- 559899 V. Invention Description (37) When the semiconductor layer is made of a heterojunction structure, its degree of freedom can be expanded 'and various heterojunction structures can be developed. For example, BP (band gap 2eV) with a small band gap in the past cannot match the GaN line lattice of BP with a GaNQ 97 P ο · 〇3 (band gap 3 e V) '. . On the other hand, from the BP related to the present invention, especially the BP with a band gap greater than 3eV, since it can constitute a barrier layer that imparts a barrier effect on GaN 0.97 P .. 3, it can be made a "carrier" The lattice matching system is a heterogeneous joint structure. From such heterogeneous junctions, as described above, there are heterogeneous junction devices for obtaining environmentally-resistant TEGFETs, Hull elements, and the like. If a TEGFET using the BP or BP mixed crystal with a large band gap according to the present invention is used as a buffer layer, leakage of gate current can be particularly suppressed, and therefore, a TEGFET with excellent mutual conductance (gm) can be obtained. In addition, if the Hull element is composed of a B P or B P-based mixed crystal with a large band gap as described in the present invention, a buffer layer can suppress the leakage of the operating current, thereby achieving a Hull element with high integrated sensitivity. A semiconductor layer made of the BP or BP-based mixed crystal described in the present invention can exhibit a larger band gap than the conventional one, so it can create a variety of semiconductor layers and a large deviation (ba η d-〇ffset) that has not been achieved before. Heterogeneous joint construction. The heterojunction structure of a semiconductor layer made using the BP or BP-based mixed crystal described in the present invention is a heterojunction structure with a large discontinuity as described above, and therefore it is particularly superior to being used as a barrier layer. (Embodiment) -39- 559899 V. Description of the invention (38) (Embodiment 1) In this embodiment 1, the group III nitride semiconductor LED using the BP semiconductor layer of the present invention will be taken as an example to specifically describe the present invention. Fig. 6 schematically shows a cross-sectional structure of the Pn junction type LED 60 according to the first embodiment. The laminated structure 61 for LED60 is a p-type doped with boron (B), and a S i single crystal having a (1 1 1) plane is configured as a substrate 601. The low-temperature buffer layer 6 0 2 on the plate 6 0 1 is composed of boron phosphide (BP) as a main body in an amorphous state in a grown (as-g 1 · 0 w η) state. The low-temperature buffer layer 602 is grown by triethylboron (C2H5) 3B) / phosphine (PH3) / hydrogen (H2) at normal pressure MOCVD method at 350 ° C. The low-temperature buffer layer 602 has a layer thickness of about 12 nm. On the surface of the low-temperature buffer layer 602, a p-shaped BP layer doped with magnesium (Mg) at a temperature of 950 ° C is stacked using the above-mentioned MOCVD vapor phase growth method. Taken as the lower barrier layer 603. As a doping source of magnesium, dicyclopentyl: alkenyl (c y c 1 o p en t a d i en y 1) magnesium (b i s-(C 5 Η 5) 2 M g) was used. The carrier concentration of the lower barrier layer 603 is about 7xl018 cnT3. The layer thickness is approximately 0.8 // m. The dependence of the index of refraction and attenuation coefficient on the wavelength of the BP layer of the lower barrier layer 603 at room temperature is shown in FIG. 7. It is concluded that the attenuation coefficient (= k) on the wavelength side shorter than about 45 Onm has a tendency to increase sharply. For example, with a refractive index of about 3.21 and a decay coefficient of about 0.0 2 9 at a wavelength of 45 nm, η = 3. 2 8 and k = 0 at a wavelength of 3 80 nm. Π 2 0. -40- 559899 5. Explanation of the invention (39) Figure 8 shows the imaginary part of the complex permittivity obtained from η and k 値 (ε2 = 2 · η ·). (Refer to the above-mentioned "III-V compounds" "Semiconductors" (p. 16 8 ~ 17 1) and the energy of photons. It shows that ε2ε decreases with the increase of photon energy. In addition, the photon energy obtained from the ε2 切片 slice is approximately 3.1eV. Therefore, the figure shows that the band gap of boron phosphide (BP) crystals that make the lower barrier layer 603 at room temperature is about 3.1eV. The band gap at room temperature is about 3.1 The superposition of the BP lower barrier layer 603 on eV matches the lattice of boron phosphide (BP), and the Mg-doped p-shaped gallium nitride (GaN 0.97P) with a phosphorus composition ratio of 0.03 (= 3%). () 3) layer as the light-emitting layer 604. The band gap between the BP of the lower barrier layer 603 and the light-emitting layer (band gap at room temperature of 2.9 eV) made of GaN 0.97P0.03. The difference is about 0.2eV. The light-emitting layer 604 made of GaN 0.97P (). () 3 of the cubic crystal is a trimethylgallium ((CH3) 3Ga) / PH3 / H2 system at 950 at atmospheric pressure. Growth at a temperature of ° C. The carrier concentration of the light-emitting layer 604 is about 3x1 01 7 cm _3. The layer thickness is about 0.3 // m. On the light-emitting layer 6 0 4, an n-shaped boron phosphide (Β Ρ) with a thickness of about 0.3 m // is used as the upper barrier layer 6 0 5 The upper barrier layer 6 0 5 is grown by (C2H5) 3B / PH3 / H2 series atmospheric MCVD method at 9 5 0 ° C. The lattice constant of the upper barrier layer 605 is 4. 5 3 8 A, and the upper barrier layer The lattice constants of 605 and the light-emitting layer 604 are made consistent. The upper barrier layer 605 is also the same as the lower barrier layer 603—likely composed of BP crystals with a band gap of about 3. leV at room temperature. The upper barrier layer 60 The carrier concentration of 5 is about 2x1 018 -41-559899. 5. Description of the invention (40) cm. The lower barrier layer 60 3 and the upper barrier layer 60 5 are made of the BP semiconductor layer with the band gap of about 3.1 Ve. LeV 的 ηshaped boron phosphide with a pn junction type made of GaNmPo.in light emitting layer 6 04 constitutes a double heterogeneous (DH) junction structure type. Overlaid on the upper barrier layer 605 is a band gap of approximately 3. leV (B P) The current diffusion layer 6 0 7 is made. The Si doped layer made of the current diffusion layer 6 0 7 is a (C2H5) 3B / PH3 / H2 normal pressure MOVCD method, which is grown below 9 50 ° C. .Set current diffusion layer 6 The layer thickness of 70 is about 50 nm, and the carrier concentration is about 8 × 10 8 C111 _3. On the bottom surface of the p-shaped Si single crystal substrate 601, a p-shaped ohim electrode 609 made of aluminum (A1) is formed. In addition, an n-shaped ohmic electrode 608 made of a gold-germanium (Au.Ge) alloy is disposed on the center of the surface of the current diffusion layer 604. The diameter of the n-shaped ohmic electrode 6 0 8 is about 1 3 0 // m. Then, the Si single crystal used as the substrate 601 is cut in a direction parallel to and perpendicular to the [21 1] direction. Thus, an L E D wafer (c h i ρ) 60 with a side of about 3 0 0/2 m is obtained. A forward drive current is passed between the two ohmic electrodes 608 to 609 to emit light. The current-voltage (I-V characteristics) shows a normal rectification characteristic based on the good pn junction characteristics of the light emitting section 60 6. The forward voltage (ie, Vf) obtained from the i_V characteristic is approximately 3.1V (forward current = 20mA). In addition, the reverse voltage is about 10V (reverse current = 5 // A). When an operating current of 20 milliamperes (mA) is passed in the forward direction, blue light with a central wavelength of about 4300 nm is emitted. The half-width (helfwidth) of the luminescence spectrum is approximately -42- 559899. 5. Description of the invention (41) 2 3 n m. The luminous intensity of a wafer state measured by a general integrating sphere is about 14 microwatts (// W). In this way, a BP compound semiconductor LED with high luminous intensity is provided. (Embodiment 2) In Embodiment 2, the pn junction type diode provided with the boron phosphide (BP) layer described in the present invention is taken as an example to specifically explain the content of the present invention. Fig. 9 schematically shows the cross-sectional structure of the pn junction diode 90 of this embodiment /. Di-borane (B2H6) / (CH3) 3Ga / H2 pressure-reduced MOCVD method was superimposed on an η-shaped Si single crystal substrate 901 doped with phosphorus (P) and having a (111) plane at 400 ° (: temperature Down from boron gallium phosphide (8) < 0 & 1 _) ^) constitutes a low-temperature crystal layer 902-1. The composition ratio (= X) of boron (B) is a lattice matching of a single crystal of Si (lattice constant = 5 · 4 3 1 A). The low-temperature crystalline layer 9 0 2-1 is grown under a reduced pressure of about 1.3 × 104 Pascal (pa). The layer thickness of the low-temperature crystal layer 902-1 is about 4 nm. According to the observation by cross-section TEM method, the low-temperature crystalline layer 902-1 of Bo.wGao.98 in the as-grown state at the time of film formation is about a distance from the surface bonded to the Si single crystal group 9 0 1 The upper 1 nm region becomes a single crystal. In addition, the low-temperature crystal layer 902-1 of BG.02Ga (). 98P and the 11-shaped Si single crystal substrate 9 01 maintained good adhesion without peeling. The upper part of the low-temperature crystal layer 9 0 2-1 is composed mainly of an amorphous body. On Bo.wGao.98? Low-temperature crystalline layer 902 ″, superimposed using the above-43- 559899 V. Description of the invention (42) of the reduced pressure MOCVD reaction system, the composition of boron is given at a temperature of 95 0 ° C (= X) Si-doped η-shaped BxGauP high temperature crystalline layer with a slope of 9 0 2 -2. The composition ratio of boron (B) increases linearly from 0.02 to 1.0 in the direction of increasing the layer thickness of the high-temperature crystalline layer 90 2-2. That is, a slope is given to the composition of boron (B), so that the surface of the η-shaped high-temperature crystalline layer 902-2 becomes a boron phosphide (BP) layer. The η-shaped BxGau P (X = 0.02 to 1.0) layer to which such a composition slope is given is based on a BP crystal having a band gap of about 3.0 OeV at room temperature as a base, and therefore, it has about 3.0 OeV. Of the crystalline layer. The composition slope of boron (B) will increase with time as the amount of diborane supplied to the MOCVD reaction system, and conversely, the supply of trimethyl gallium (trimethyl g a 1 i um) will decrease with time. The layer thickness is approximately 0.4 // m. The pressure of the reaction system during the growth of the η-shaped high-temperature crystal layer 9 02 _2 is set to about 1.3 × 10 4 Pa. The composition slope of BxGa ^ P (X = 0 · 20 to 1.0) is used to grow the high-temperature crystal layer 9 0 2-2 by using a mixture of Otsunin (S i 2 Η 6)-Η 2 to mix Si. The carrier concentration was set at about 1 X 1 0 18 αι3. The analysis by the X-ray diffraction analysis method confirmed that the η-shaped high-temperature crystal layer 902-2 is a (1 1 1) directional orthorhombic crystal (BxGa = to 0.1) crystal layer. After the formation of the BxGa ^ P composition slope layer of the η-shaped high-temperature crystalline layer 902-2 is completed, most of the amorphous body in the 002.08 (). 98P low-temperature crystalline layer 902-1 is The single crystal layer exists on the basis of a single crystal layer existing in a boundary region with the Si single crystal substrate 90 1 in an as-grown state. In addition, the η-shaped BxGauPpzO.M to 1.0%) high-temperature crystalline layer 902-2 is provided by Bo which is composed of a lattice that matches the single crystal substrate 901 row-44-559899 V. Invention description (43). o2Gao.98P (lattice constant = 5.43 1 A) is a low-temperature crystalline layer over 9 0 2-1, so it becomes a continuous film that does not peel off. The buffer layer 902 is composed of a laminated structure of the above-mentioned low-temperature and high-temperature crystal layers 902-1, 902-2. An n-shaped boron phosphide (BP) layer 903 was bonded on the n-shaped high-temperature crystalline layer 902-2 by a B2H6 / PH3 / H2 series reduced pressure MOCVD method at a temperature of 95 ° C. When the n-shaped PB layer was grown at 903, a Si2H6-H2 mixed gas was used to dope Si. The carrier concentration of the n-shaped BP layer 9 0 3 is about 5 × 1 017 C111 ~ 3. In addition, the layer thickness is approximately 0.3 // m. The n-type layer 9 0 3 is composed of a PB crystal having a band gap of about 3.0 eV at room temperature. OeV 的 Magnesium (The p-type BP layer 904 is deposited by incorporating a band gap of about 3. OeV 的 Magnesium (on the η-shaped BP layer 903 by B2H6 / PH3 / H2 series reduced pressure MOVCD method at 95 (TC temperature). Mg) consists of a BP layer. The doping source of magnesium is dicyclopentadienyl Mg (bis-C5H5) 2Mg). The p-shaped layer 9 04 is composed of a wide-gap semiconductor sphalerite crystal type and B P having a low ion-binding property. Therefore, the carrier concentration can be made to be about 3 X 1 0 1 8 cm _ 3. The p-shaped layer 9 0 4 has a layer thickness of about 0.2 // m. A p-n junction structure is formed from the n-shaped BP layer 903 and the p-shaped BP layer 904 described above. On the bottom surface of the n-shaped Si single crystal substrate 901, an n-shaped ohmic (0 lim i c) electrode 906 made of aluminum (Al) is formed. In addition, a ohmic electrode 905 made of gold (Au) was arranged on the center of the surface of the p-shaped B P layer 904. The diameter of the p-shaped ohmic electrode 9 0 5 is about 1 1 0 " m. Then 'cut the Si single crystal as the substrate 9 0 1 in -45- 559899 parallel to and perpendicular to the [2 1 1] direction V. Description of the invention (44) direction' to make one side approximately 3 5 0 / / m of the diode 9 chip. Brother 10 does not show an example of the current-voltage (I-V characteristic) measured by passing a forward current between two ohmic electrodes 905 to 906. The pil-junction type BP diode of the second embodiment exhibits normal rectification characteristics based on good pn junction characteristics. In addition, the reverse voltage is about 15V (reverse current = 10 # a), thereby providing a compound semiconductor pn junction diode having a high withstand voltage. (Embodiment 3) In Embodiment 3, the content of the present invention will be specifically described using an npn-junction heterobipolar transistor (HBT) having a bp-based mixed crystal containing boron phosphide (BP) of the present invention as an example. FIG. 11 is a schematic sectional view showing an npn junction type HBT according to the third embodiment. A diborane (B2H6) / (CH3) 3Ga / H2 pressure-reduced MOCVD method was used on a Si single-crystal substrate 101 doped with phosphorus (P) and having an η shape of 1000, at 3 5 0 A low-temperature buffer layer 102 made of boron phosphide gallium (BxGai_xP) is stacked at a temperature of ° C. The composition ratio (= X) of boron (B) was made to be a single crystal of Si (lattice constant = 5.43 1A) with a lattice matching of 0.02. The low-temperature buffer layer 102 is grown under a reduced pressure of about 1.3 × 104 Pascal (Pa). The layer thickness of the low-temperature buffer layer is about 14 nm. On the low-temperature buffer layer 102 of Bo.wGao. ^ P, each of the functional layers described below was sequentially stacked using the above-mentioned reduced pressure MV C D reaction system at a fixed growth temperature of 850 ° C. The carrier concentration (n (n-shaped) or P (P-shaped)) and layer thickness of each functional layer 10 3 to 108 are prepared as follows -46- 559899 V. Description of the invention (45), so that A laminated structure 11 constituting a use such as HB T 1 0. (1) The composition ratio of boron (= X) was linearly increased from 0.02 to 1.0 from the interface bonded to the BP low-temperature buffer layer 102 toward the surface of the layer. That is, a collector layer 1 0 3 (η = 9 X 1 0 17 cm, t = 0.5 0 // m) is formed from a slope layer composed of Si-doped n-shaped BxGa ^ P with boron phosphide (BP) on the surface. (2) Sub-collector layer 104 made of Si-doped n-shaped BP with n = 2xl018cnT3, t = 0.10 // m. (3) An intermediate layer made of Si doped with n-type gallium nitride (G aN) in a facet crystal with n = 3xl018 cm · 3 and t = 0.05 // m. (4) p = 3xl019⑽, t = 0.0 1 // m, p-type phosphorus boron nitride (BPg.97N (). 〇3) doped with magnesium (Mg) doped at room temperature with a band gap of about 3eV Base body 1 06. (5) An emitter layer 107 made of Si-doped n-shaped gallium nitride (GaN) with n = 4xl018 cm _3, t = 0.20 // m, and a band source at room temperature of about 3.2eV. (6) A contact layer 108 made of Si-doped n-type gallium nitride (G aN) with n = 7xl018⑽_3, t = 0.10 // m, and a band source at room temperature of about 3.2 e V. Then, by using a general plasma etching method using an argon (Ar) / methane (CH4) / hydrogen (H2) mixed gas, a stepwise etching is performed on the laminated structure 11 for HBT to expose the collector layer 108 and the base layer 106. And the surface of each functional layer of the sub-collector layer 104. The above-mentioned intermediate layer 105 is to prevent the erosion of the sub-collector layer 104, thereby achieving the effect of barely exposing the surface of the sub-collector layer 104. On the surface of the collector layer 108, an emitter electrode 109 made of an alloy of gold and germanium (Au97 wt% _Ge3 wt%) is provided. Emitter electrode 1 09 之 平 __ -47- 559899 5. Description of the invention (46) The shape is a square with a side length of about 1 1 0 // m. A collector electrode 110 made of the same AtGe alloy as described above is provided on the secondary collector layer 104 exposed through the above-mentioned etching process. Each of the electrodes 1 09, 1 10 for the n-shaped layer was vapor-deposited by a general vacuum vapor deposition method, and then subjected to an alloying heat treatment (alloy) at a temperature of 42 ° C for 5 minutes. Then, a band-shaped base electrode 111 made of a gold-zinc (Au95% by weight, Zn5% by weight) alloy is provided on the P-shaped base layer 106 by a selective patterning method using a lithographic printing technique. Then, an alloying heat treatment was performed at a temperature of 400 ° C for 2 minutes. After that, it is cut into individual semiconductor elements. In the state where the obtained HBT emitter electrode 109 and the collector electrode 1 10 are applied with a voltage of 2.5 V (the so-called collector voltage), the base of the base layer 106 having a sheet resistance of about 3 60 Ω / □ is applied. The current varies in the range of 0 to 50 microamperes (// A). The DC current amplification factor (P = IcE / UB) for the magnitude of the change in base current is approximately 95. Accordingly, according to the present invention, a HBT with high DC amplification and stability can be provided. (Embodiment 4) This embodiment 4 specifically describes the content of the present invention by taking a photodetector for ultraviolet field applications provided with the boron phosphide (BP) semiconductor layer of the present invention as an example. Fig. 12 is a schematic sectional view showing the structure of a light receiving element 20 according to the fourth embodiment. Borrowing triethylboron ((C2H5) 3B / PH3 / H2 series atmospheric pressure (approximately atmospheric pressure) M0CVD method at 380-48-559899 on a sapphire substrate 201 with (001) (C surface) (47) The temperature F accumulates the low-temperature buffer layer 202 made of boron phosphide (BP). The layer thickness of the low-temperature buffer layer 202 is about 5 nm. The above-mentioned normal pressure M is used on the BP low-temperature buffer layer 202. The 0 CVD method deposits a silicon (Si) -doped η-shaped boron phosphide (BP) active layer 203 at a temperature of 8 2 5 ° C to form a multilayer structure 21 for the light receiving element 20. The active layer 2 0 3 series It is composed of a PB semiconductor layer with a band gap of about 3.leV at room temperature. The carrier concentration of the active layer 203 is about 2xl01 () on _3, and the layer thickness is about 1.8 // m. Then, the fabricated light receiving element is laminated. The structure 21 is subjected to plasma etching to etch the central portion of the surface of the active layer 203 into a circular shape. The etching operation is performed on a circular area with a diameter of about 1 2 0 // m, and the depth of the etching is about 0. 1 A m. In this field, a Schottky electrode of a three-layer structure made of titanium (Ti) / platinum (Pt) / gold (Au) with a diameter of about 100 // m is formed. 4. In addition, a ring-shaped ohmic electrode 205 formed of a three-layer structure of gold, germanium (Au.Ge), nickel (Ni), and gold (Au) is arranged on the periphery of the Schottky electrode 204 to constitute the light receiving element 20. The ring-shaped electrode 205 is formed on a circumference having a diameter of about 2 2 0 // m at the center of the center of the above-mentioned Schottky electrode 204. The fourth embodiment is based on the low-temperature buffer layer 202. The base layer is further stacked with the active layer 203. Therefore, the active layer 203 becomes a good crystalline layer, whereby the idling current when a reverse voltage of -2 V is applied between the ohmic electrode 20 5 and the Schottky electrode 204 Reduced to lxl (T8A / cnT2. In addition, the cut-off wavelength is about 40nm, so according to the present invention, it can provide a light receiving element in the near-ultraviolet field with excellent idling current characteristics. -49- 559899 5. Description of the invention (48) (Effects of the invention) According to the present invention, the use of boron phosphide (BP) with a high bandgap range not previously available at room temperature of 2 · 8 ev or more and 3 · 4 e V or less at room temperature or the use of ββ The BP-based mixed crystals obtained by crystal crystallization form a compound semiconductor device, and therefore have a wide band gap performance. Operates at high temperature and can form the effect of high withstand voltage semiconductor elements. In particular, in addition to having a wide band gap, it is also used as a β-P or β-P series of sphalerite crystals with low ion-binding properties. Mixed crystals can therefore easily form a P-shaped conductive layer with a concentration of normal pores, thereby having a semiconductor element capable of providing a P-shaped semiconductor layer with a low resistance as a functional layer. A pn junction type diode using a semiconductor layer made of the BP of the present invention or a semiconductor layer made of a BP mixed crystal can obtain a diode that exhibits normal rectification characteristics and high withstand voltage. A blue light-emitting element having a high light-emitting intensity can be obtained from an LED using a semiconductor layer made of the BP of the present invention or a semiconductor layer made of a BP-based mixed crystal. In addition, from a light-receiving element using a semiconductor layer made of BP of the present invention or a semiconductor layer made of BP-based mixed crystal, a light-receiving element for the near-ultraviolet field having excellent idling current characteristics can be obtained. In addition, a TEGFET using a semiconductor layer made of B P or a semiconductor layer made of B P-based mixed crystal of the present invention can obtain an electric field effect type transistor that exhibits high electron mobility. In addition, from a HBT using a semiconductor layer made of the BP of the present invention or a semiconductor layer made of a BP-based mixed crystal, a stable and stable HBT can be obtained. In addition, from -50 to 559899 V. Description of the invention (49) A Hall element with a semiconductor layer made of the BP of the present invention or a semiconductor layer made of a BP mixed crystal can be obtained with excellent heat resistance. High sensitivity Hull element. According to the method for forming a wide band gap BP or BP-based mixed crystal layer according to the present invention, it is possible to stably form boron phosphide (BP) with a high band gap in a range not previously found at room temperature of 2.8eV to 3.4eV. Or BP mixed crystal effect. Therefore, it is possible to form various heterogeneous bonding structures with other semiconductors. For example, from the BP having a band gap within the scope of the present invention, the effect of forming a heterogeneous bonding structure that imparts a barrier effect on gallium phosphorous nitride (GaNP mixed crystal) is obtained, which cannot be obtained from the conventional BP with a band gap of 2 eV. of. In addition, according to the method for forming a BP or BP-based mixed crystal layer according to the present invention, even when a single crystal having a lattice mismatch relationship is used as a substrate material to obtain a laminated structure required for a compound semiconductor, it can BP or BP mixed crystals that mitigate the mismatch between the substrate material and the constituent layers of the laminated structure constitute a buffer layer. Furthermore, a BP layer or BP with excellent crystallinity can be formed on a buffer layer that can mitigate lattice mismatch. Mixed crystal layer. Therefore, according to the forming method of the present invention, it is possible to form a laminated structure of a BP or BP-based mixed crystal layer having excellent crystallinity, and further to provide an effect of providing a compound semiconductor device having excellent characteristics. (Brief description of the drawing) Figure 1 is a correlation diagram of the band gap at room temperature of the III-V compound semiconductor and the average atomic number of the constituent elements. -51-559899 5. Explanation of the invention (50) The second graph is a photon energy dependence of the absorption coefficient of the BP semiconductor layer of the present invention. FIG. 3 is a spectrum of cathode luminescence of a B P semiconductor layer according to the present invention. ° FIG. 4 is a schematic cross-sectional view of a TEGFET composed of a BP semiconductor layer according to the present invention. Fig. 5 is a schematic cross-sectional view of a laminated structure using a Hull element composed of a BP semiconductor layer according to the present invention. Fig. 6 is a schematic sectional view of a pn-junction LED according to the first embodiment of the present invention. Fig. 7 is a graph showing the wavelength dependence of the refractive index and the attenuation coefficient of the B P layer according to the first embodiment of the present invention. Fig. 8 is a diagram showing the relationship between the imaginary part of the dielectric constant of the BP layer and the photon energy according to the first embodiment of the present invention. Fig. 9 is a schematic sectional view of a pn junction diode according to the second embodiment of the present invention. Fig. 10 is a graph showing the current-voltage characteristics of the pn junction diode according to the second embodiment of the present invention. FIG. 11 is a schematic diagram showing a cross-sectional structure of an nPn junction HBT according to Embodiment 3 of the present invention. Fig. 12 is a schematic sectional view of a light receiving element according to Embodiment 4 of the present invention. -52- 559899 V. Description of the invention (51) (Description of symbols) 1 0: Η BT 101: η-shaped Si single crystal substrate 1 0: Collector layer 1 〇5: Intermediate layer 1 0 7: Emitter layer 1 0 9: Emitter layer 1 1 1: Base electrode 21: Multilayer structure for light receiving element 202: BP low temperature buffer layer 204: Schottky electrode 40: Two-dimensional electron short-acting transistor 4 0 2: Low temperature crystal layer 404 : Electron walking layer 406: Electron supply layer 4 0 8: Gate electrode 4 1 0: Drain electrode 5 〇1: Substrate 5 0 3: Second buffer layer 5 0 5: Spacer layer 60: LED 601: Substrate 6 0 3: lower barrier layer 6 0 5: upper barrier layer 6 0 7: current diffusion layer 6 0 9: p-shaped ohmic electrode 901: substrate 902-1: low-temperature crystalline layer 9 0 3: n-shaped BP layer 9 0 5: ρ Shaped ohmic electrode 11: laminated structure for HBBT 102: low-temperature buffer layer 104 • sub-collector layer 1 0 6: base layer 1 0 8: contact layer 1 1 0: collector electrode 20: light receiving element 201: sapphire substrate 2 0 3: Β active layer 2 0 5: ohmic electrode 401: substrate 403: high-temperature crystalline layer 4 0 5: spacer layer 4 0 7: contact layer 4 0 9: source electrode 4 1 1: recessed portion 5 02: first 1 buffer layer 5 0 4 ·. Magnetic induction layer 6 1 Multi-layer structure for LED 602: low-temperature buffer layer 604: light-emitting layer 606: light-emitting portion 608: n-shaped ohmic electrode 9 0: diode 9 0 2: buffer layer 9 0 2-2: local temperature crystalline layer 904: p Shaped BP layer 9 0 6: n-shaped ohmic electrode -53-