M397604 五、新型說明： 【新型所屬之技術領域】 本創作係關於一種蕭特基二極體，尤指一種可減少逆 向漏電流之多重表面電場屏蔽式蕭特基二極體。 【先前技術】 簡單的蕭特基二極體由半導體基板（通常為N型）及位 於基板上之金屬層所組成，半導體基板中的自由電子能階 較金屬層中的自由電子能階低，在沒有偏壓的情況下月，匕^ 導體基板中的電子無法躍遷至高能階的金屬層中，形0 特基障礙，當施加順向偏壓時，半導體基板中的自由電子 獲得能量而可躍遷到高能階的金屬層中， /王土电；，而因 為金屬層中沒有少數的載子，所以無電荷儲存逆向回復 的時間短…，蕭特基二極體適用於高頻整流應用，蕭 特基障礙越小順向電壓值就可越小，，然而，在蕭心障礙 不夠大的情形下施加逆向電壓，蕭特基二極 流高，此為蕭特基二極體的最大缺點。 D漏- ，，如圖4所示者’為了改善此缺點，在習用技術中，先 在半導體基板8上沈積一層低摻雜的半 產生以日90,並在溝槽90的内壁沈積氧化物層^ :覆蓋金屬層H，在這種結構下’施加逆向電壓 荷可累積在氧化物@ 10,產生表面電場屏蔽作用，限制電 流導通’㈣有較之前無氧化物時降低漏電 有效的達料場屏蔽的效果，必_加_8 2 了更 J ’衣度，同 3 M397604 時為了在正向導通時’電流導通的有效面積增加，必須將 溝槽80寬度窄化，如此「深寬比」大的溝槽8〇在製程上 有一定的難度，因此無法同時兼顧屏蔽電場及高導通電流 的優點》 【新型内容】 本創作之目的在於提供一多重表面電場屏蔽式蕭特基 二極體，期望藉由此設計改善蕭特基二極體逆向漏電流過大 的問題，且提供足夠的電流導通有效面積，進而使蕭特基二 極體可應用在更多的領域。 ▲為達成前述目的，本創作提供了一種多重表面電場屏蔽 式蕭特基二極體係包含有： 一基板； -第-介電層，係以間隔方式形成在該基板表面，相 鄰第一介電層間形成間隙；M397604 V. New Description: [New Technology Area] This creation is about a Schottky diode, especially a multi-surface electric field shielded Schottky diode that reduces reverse leakage current. [Prior Art] A simple Schottky diode consists of a semiconductor substrate (usually an N-type) and a metal layer on the substrate. The free electron energy level in the semiconductor substrate is lower than the free electron energy level in the metal layer. In the absence of a bias voltage, the electrons in the conductor substrate cannot be transitioned to the high-energy metal layer, and the shape is 0. When the forward bias is applied, the free electrons in the semiconductor substrate can obtain energy. Transition to the high-energy metal layer, / Wang Tudian; and because there are not a few carriers in the metal layer, the time for the reverse recovery of no charge storage is short..., the Schottky diode is suitable for high-frequency rectification applications, The smaller the Schottky barrier, the smaller the forward voltage value can be. However, when the Xiaoxin barrier is not large enough, the reverse voltage is applied, and the Schottky diode flow is high. This is the biggest disadvantage of the Schottky diode. . D leakage - , as shown in FIG. 4 'In order to improve this disadvantage, in the conventional technique, a low-doped half is deposited on the semiconductor substrate 8 to produce a day 90, and an oxide is deposited on the inner wall of the trench 90. Layer ^: Covering the metal layer H. Under this structure, 'applying a reverse voltage load can accumulate at the oxide @10, resulting in a surface electric field shielding effect, limiting the current conduction'. (4) There is an effective material for reducing leakage when there is no oxide before. The effect of the field shielding must be _8 2 and the J 'clothing degree. When the same as the 3 M397604, in order to increase the effective area of the current conduction during the forward conduction, the width of the groove 80 must be narrowed, so that the "aspect ratio" The large groove 8〇 has certain difficulty in the process, so it is impossible to take into consideration the advantages of shielding electric field and high on-current at the same time. [New content] The purpose of this creation is to provide a multi-surface electric field shielding Schottky diode. The body is expected to improve the problem of excessive reverse leakage current of the Schottky diode by this design, and provide sufficient current conduction effective area, so that the Schottky diode can be applied in more fields. ▲ In order to achieve the foregoing objectives, the present invention provides a multi-surface electric field shielded Schottky diode system comprising: a substrate; a first dielectric layer formed on the surface of the substrate in a spaced manner, adjacent to the first dielectric layer Forming a gap between the electrical layers;
▲ 夕曰曰矽層，形成於所述第一介電層之内部，其中， 该多晶矽層之部分區域#外 覆 兑係外路於第一介電層而未被其包 並填滿各第一介電………一"層之表面， 電3間的間隙，該磊晶半導體 式形成複數溝槽，H… ^ U ^ 一笛A 向下延伸至外露的多晶矽層頂部； 第-"電層，係覆蓋於磊晶半導體層上； 、.冓样：金位屬係覆蓋於該第二介電層表面，且填充於該此 4槽内’位於溝样由 〆二 形成蕭特基接觸奴該金屬層與蟲晶半導體層之側壁係 4 M397604 藉由上述結構，因為介電層具有介電性質，當施與逆向 偏壓時，電荷會累積在第一介電層及第二介電層中，第一介 電層及第二介電層中累積的電荷分別在磊晶半導體層中形 成一靜電場，因此，第—介電層及第二介電層間具有兩個靜 電場’在此兩個靜電場作用·，發生多4電場屏蔽效應進而 降低逆向漏電流，並利用調整磊晶半導體層的厚度來增加 電流導通時的有效面積。▲ an 曰曰矽 layer formed inside the first dielectric layer, wherein a portion of the polysilicon layer is externally applied to the first dielectric layer without being wrapped and filled with each A dielectric ... ... a " surface of the layer, the gap between the electricity 3, the epitaxial semiconductor form a complex trench, H... ^ U ^ A flute A extends down to the top of the exposed polycrystalline layer; the first -" The electric layer is covered on the epitaxial semiconductor layer; and the gold-like genus covers the surface of the second dielectric layer, and is filled in the 4-slot. The contact layer of the metal layer and the sidewall layer of the insect crystal semiconductor layer 4 M397604. With the above structure, since the dielectric layer has a dielectric property, when a reverse bias is applied, charges are accumulated in the first dielectric layer and the second In the dielectric layer, charges accumulated in the first dielectric layer and the second dielectric layer respectively form an electrostatic field in the epitaxial semiconductor layer, and therefore, two electrostatic fields are present between the first dielectric layer and the second dielectric layer. 'In these two electrostatic fields, · 4 electric field shielding effects occur, which reduces the reverse leakage current. The thickness of the epitaxial semiconductor layer is adjusted to increase the effective area when the current is turned on.
L貫施方式】 如圖1所示’係本創作之多重表面電場屏蔽式蕭特基二 極體之較佳實施例’此多重表面電場屏蔽式蕭特 包含一基板]、一第一介電層2'一多 石’、 ^ ^ ^ 夕曰曰矽層3、一磊晶半 導體層4、一第二介電層5及一金屬層6。 該基板1可為N型半導體材料，例如矽、冑，並摻雜 有五價離子’例如砷、4，因此在N型半導體基板”形 成多餘的自由電子。 乂 乂該第一介電層2以間隔方式形成在該基板1表面，故 :鄰的第一介電層2之間形成有間陽:2〇,所述第一介電 -可為氧化物層，以限制電子流可流動的路徑。 該多晶⑦層3’係形成於所述第—介電層2内部，其中， 。玄夕晶矽層3之部分區域係外霞笼 包覆。 A料^第—介電層2而未被其 該以半導體層4，係以與該基板彳㈣導電性 構成，其係覆蓋於部份第— 科 ^ ;丨萆層2的表面，並壤 第—介電層2間的間隙20，节石曰主道脚 、；" 及從日日+導體層4形成複數個 5 、’曰4广各溝槽40向下延伸至外露的多晶矽層3之頂部， 並可稭由調整泫磊晶半導體^ 4的厚度來增加電流導通時 :有效面肖纟實％例中該磊晶半導體層4為一 N型磊晶 半導體層4，其係為半導體材料例如矽、鍺，並摻雜有五 價離子，例如坤、德，α # ιΑ 且其摻雜物的濃度小於該基板1中 摻雜物的濃度。L-through mode] As shown in FIG. 1 , a preferred embodiment of the multi-surface electric field shielded Schottky diode of the present invention is a multi-surface electric field shielded Schott comprising a substrate], a first dielectric The layer 2'-a stone', the ^^^ layer 3, an epitaxial semiconductor layer 4, a second dielectric layer 5, and a metal layer 6. The substrate 1 may be an N-type semiconductor material, such as germanium, germanium, and doped with pentavalent ions such as arsenic, 4, thus forming excess free electrons on the N-type semiconductor substrate. 乂乂 The first dielectric layer 2 Formed on the surface of the substrate 1 in a spaced manner, so that: between the adjacent first dielectric layers 2 is formed a meta-positive: 2 〇, the first dielectric - may be an oxide layer to limit the flow of electrons The polycrystalline 7 layer 3' is formed inside the first dielectric layer 2, wherein a part of the layer of the eclipse layer 3 is covered by an outer cage. A material ^ first dielectric layer 2 The semiconductor layer 4 is not electrically connected to the substrate (4), and is covered on the surface of the portion of the surface layer 2, and the gap between the first layer and the dielectric layer 2 20, the main stone foot of the stone, and "and" from the day + conductor layer 4 form a plurality of 5, '曰4 wide groove 40 extends down to the top of the exposed polycrystalline layer 3, and can be adjusted by straw When the thickness of the epitaxial semiconductor 4 is increased to increase the current conduction: the effective surface is in the case of %, the epitaxial semiconductor layer 4 is an N-type epitaxial semiconductor layer 4, A semiconductor material such as silicon, germanium, and doped with a pentavalent ion, e.g. Kun, Germany, α # ιΑ and the concentration of the dopant is less than a dopant concentration of the substrate.
該第二介電層5’係覆蓋於該磊晶半導體層4上方，該 第二介電層5可為氧化物層。 X金屬層6係填於該些溝槽4〇内且覆蓋於該第二介電 層5之表面，填充於該些溝槽4〇内部之該金屬層6與磊晶 半導體層4側壁之間形成蕭特基接觸。The second dielectric layer 5' is over the epitaxial semiconductor layer 4, and the second dielectric layer 5 may be an oxide layer. The X metal layer 6 is filled in the trenches 4 and covers the surface of the second dielectric layer 5, and is filled between the metal layer 6 and the sidewall of the epitaxial semiconductor layer 4 inside the trenches 4? Forming a Schottky contact.
本創作之多重表面電場屏蔽式蕭特基二極體，在無偏壓 的清况下，基板1及磊晶半導體層4中的載子無法躍遷至 自由電子能階較高的金屬層6中；在本創作一較佳實施例， 基板1與磊晶半導體層4均為N型半導體，且第―、第二 介電層2、5均為氧化層’如圖2所示者，當施加順向偏壓 時，N型半導體基板自由電子獲得能量而可躍遷到高 能階的金屬層6中，產生電流，電子流由N型半導體基板] 通過第一介電層2間的間隙20,進入N型磊晶半導體層4, 再克服金屬層6與N型磊晶半導體層4側壁之間的蕭特基 障礙而導通。 如圖3所示者’當施加逆向偏壓時，自金屬層6甲的游 離的電荷會累積在第一介電層2及第二介電層5上，因此 在接近第一介電層2及第二介電層5的N型磊晶半導體層 4中分別形成一靜電場7，因此，第一介電層2及第二介電 6 M3y/0U4 半導體層4中具有兩個靜 =場7作用下’產生多重電場屏蔽效在 ㈣游離自由電子，進而降低逆向漏電流。 層 :合上述說明可得知’本創作藉由第一 介電層5的設計，使雷 及弟一 雷塥7,… I電何可以累積在其上，分別形成-靜 # u i多重電場屏蔽作用而排斥自由電子，減少 逆向漏電w ’使仔蕭特基二極體之漏電缺點獲得改善，進 而使蕭特基二極體能做更廣泛的應用。 。 【圖式簡單說明】 1係、本創作多重表面電場屏蔽式蕭特基二極體之剖 面不意圖。 圖2係本創作多重表面電場屏蔽式蕭特基二極體在順 向電壓下之操作示意圖。 、 圖3係本創作多重表面電場屏蔽式簫特基二 φ向電壓下之操作示意圖。 體在逆 • 圖4係習用蕭特基二極體之剖面示意圖。 【主要元件符號說明】 1基板 20間隙 4磊晶半導體層 5第二介電層 7靜電場 2第一介電層 3多晶<5夕層 40溝槽 6金屬層 8半導體基板 7 M397604 9半導體層 90溝槽 1 0氧化物層 11金屬層In the multi-surface electric field shielded Schottky diode of the present invention, in the unbiased condition, the carriers in the substrate 1 and the epitaxial semiconductor layer 4 cannot be transitioned to the metal layer 6 having a higher free electron energy level. In a preferred embodiment of the present invention, the substrate 1 and the epitaxial semiconductor layer 4 are both N-type semiconductors, and the first and second dielectric layers 2, 5 are both oxide layers' as shown in FIG. When forward biased, the N-type semiconductor substrate freely obtains energy and can transition into the high-level metal layer 6 to generate a current, and the electron flow is passed through the gap 20 between the first dielectric layers 2 through the N-type semiconductor substrate. The N-type epitaxial semiconductor layer 4 is further turned on against the Schottky barrier between the metal layer 6 and the sidewall of the N-type epitaxial semiconductor layer 4. As shown in FIG. 3, when a reverse bias is applied, the free charge from the metal layer 6A is accumulated on the first dielectric layer 2 and the second dielectric layer 5, and thus is close to the first dielectric layer 2. And an electrostatic field 7 is formed in each of the N-type epitaxial semiconductor layers 4 of the second dielectric layer 5, so that the first dielectric layer 2 and the second dielectric 6 M3y/0U4 semiconductor layer 4 have two static fields. Under the action of 7 'generate multiple electric field shielding effect (4) free free electrons, thereby reducing the reverse leakage current. Layer: With the above description, it can be known that 'this creation is made by the design of the first dielectric layer 5, so that Lei and his brother a Thunder 7, ... I can accumulate on it, respectively, forming a static - ui multiple electric field shielding The role of repelling free electrons and reducing the reverse leakage w' improves the leakage shortcomings of the Schottky diode, which in turn enables the Schottky diode to be used more widely. . [Simple description of the diagram] The 1 series, the original surface of the multi-surface electric field shielded Schottky diode is not intended. Figure 2 is a schematic diagram of the operation of the multi-surface electric field shielded Schottky diode in the forward voltage. Figure 3 is a schematic diagram of the operation of the multi-surface electric field shielded 箫 基 二 φ voltage. Body in the reverse • Figure 4 is a schematic view of the Schottky diode. [Description of main components] 1 substrate 20 gap 4 epitaxial semiconductor layer 5 second dielectric layer 7 electrostatic field 2 first dielectric layer 3 polycrystalline < 5 layer 40 trench 6 metal layer 8 semiconductor substrate 7 M397604 9 Semiconductor layer 90 trench 10 oxide layer 11 metal layer