1325634 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種影像感測器，尤指一種包含一遮蔽電極之影 像感測器’以解決載子跨越干擾之問題。 【先前技術】 互補式金屬氧化物半導體（complementary metal oxideBACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an image sensor, and more particularly to an image sensor comprising a shield electrode to solve the problem of carrier crossover interference. [Prior Art] Complementary metal oxide semiconductor (complementary metal oxide semiconductor)
semiconductors ’ CMOS )或電荷搞合裝置（charge coupled device， CCD)等影像感測器是一種矽半導體裝置，設計用來捕捉光子（光 線）’並將光子轉換成電子。經轉換為電子後，電子就會被傳輸， 並再次被轉換為可量測之電壓，而轉成數位資料。業界已進行研 究一種以氫化非晶矽（hydrogenated amorphous silicon，a-Si:H)為 基礎而堆疊於CCD或CMOS元件上的影像制ii，以追求具有 優良於傳統CCD或CMOS影像感測器之表現，其敘述如下。因 其堆疊結構所帶來的高集光有效面積比（flll fact〇r)能使得整個像 素面積都能用來感測光子，翻己合a_Si:H材料有效轉換能量的特 性，便能達到高量子效率。然而，在已知研究中，此種感測器仍 然有跨越干擾（_-talk)、影像延遲（imagelag)以及漏電流訊 號等問題。其中載子跨越干擾相鄰像素的問題尤其會造成嚴重的 解析度與均勻性不足的問題’也會在像素間造成色彩上的跨越干 擾，導致色彩失真。此外，在優Η材料中的深陷或場發射 子輸送機制會導致低載子移動速率，進而很容易發生影像延 題，因而在動態影像之晝面中產生亮點殘影之情形。特別士之 5 1325634 由於像素之全部訊號無法在單一晝面中被讀取，因此當發生影 像延遲問題時，於低訊號位階中不可能再生真實的色彩。再者， ^電""問題主要成因於光導層巾由金屬電極至p型層(p-layer)或η 尘層(n layer)的電洞電子注入遂穿（加皿^丨）情形其會在暗幕產 士很f雜訊。所以，為了能與傳統矽基CCD或CM〇s影像感測 相肌爭，上述三個主要問題需要被解決，以提供較佳晝面品質。 目削使用a-Si:H材料之技術已發展出具有下列材料： ()透明導電層，材料如氧化銦錫（Indium Tin Oxide，ITO ；); (二）硼（boron)重摻雜p型層，包含有氫化非晶質碳化矽 (hydrogenated am〇rph〇us讪⑽，弋亂丑）材料，用來 收集在本徵層（intrinsie layCT，i_laye〇產生的光致電洞傳輸至 ITO ； (二）a-Si:H本徵層，主要作為光致電子_電洞對產生層； (四） 鱗（phosphorus)重摻雜n型層，包含有氫化碳摻雜非 晶矽（hydrogenated carbon doped 麵抽〇仍 silic〇n)材料作為從 本徵層產生之電子的接收者，以傳輸至金雜素電極；以及 (五） 金屬像素電極，設於n型層下方且連接於電晶體，其係 垂直堆疊於位於矽基底上2CM〇s電路上方。 八 第1圖顯示出具有一本徵層/n型層接合之p_i-n異質接面的能 帶圖。電荷對電壓轉換率主要係決定於_電容之大小，並且^ 由增厚本徵層而最小化。 ' 1325634 為了能在a-Si:H本徵層達到較高量子效率，必須於較大厚度 中藉由最佳化氫原子的濃度產生較長壽命的少數載子（min〇rit^ earner)以及較高的載子遷移率來改善光導電性以及光吸收性。同 時，位於ιτο層下方的硼重摻雜p型層可以甲烷基a_Sic.H ( based a-SiC:H)層取代，以與a-Si:H本徵層形成異質接面。由於 碳化矽具有較大的光學能隙〇argeropticaI bandgap，E〇pt)，因此 能有效增強其透明度，亦能藉由擴大能帶間隙以抑制漏電流，進 而避免因遂穿效應而造成電子由I 丁〇層發散至p型層。再者， (x-S^CH材料亦可適用於n型層中，以藉由降低像素電極間之n塑 層導電性㈣免像素之間的橫向載子跨越干擾。此設計亦能有效 阻擋電洞由氮化鈦（titaniumnitride，TiN)像素電極發散至η型層， 其係相同於電子遂穿至ρ型層之情況^然而，α·%材料的高密度 冰fe情形（deeptrap)會帶來漏電流以及影像延遲等問題。 ^再者，在像素電極的邊角與^層交界處會發生更嚴重的問 ^ ’其係由於電場強度會局部集巾而使得能帶彎曲，如第2圖所 心丁之邊緣處。其巾因遂穿而造成的制遷移機率會變大，進而 曰上反向偏[jf形的漏電流。此外，自構成的η型層亦會 有效黏附於TlN像素電極上，而不會有脫落（peeiing_〇tf)之情形， p ;張力的關係’像素電極邊角上被施壓的α-SiC膜可能會有高 在度的，造成和影像延遲同樣嚴重的像素缺陷，如第2圖所 示。 132卿 請參考第3 (a)圖至第4圖 有p-i-n声雄聶紝谣少旦I# 、中第3 (a)圖係為習知一具 =)圖所示之影像感測器的等效電路圖，而 = =:::設於一基底(圖未示)上、複數個像素= 及氧切絕緣層24上、—光導層14設於像 Γ由=上二及—透日輸16設於光導層14上，其中光導層 下至上包含一 η型層18、一本徵層20以及- ρ型層22，形 成所謂的堆疊p_i-n層結構。 乂 >以下將光導層14與Cpd、Csub、C】以及c2Eg電容元件—併介紹。 這些電容7L件係以第3(a)圖所示n型層/本徵層介面位於像素電極 12間隙中央的即點而定位。此處，c㈣表示以氧化姻錫㈤1賊如 • ’ IT〇)形成之透明電極Μ的電容元件，Csub表示ρ型矽基 底（圖未不）.經氧化石夕絕緣層24之電容元件，而&以及q則分 別表示相鄰金屬像素電極12的電容元件。習知影像感測器1〇的 裝置結構可假想成覆置（flipped)續道金屬絕緣半導體場效應電 晶體（metal insulator semiconductor field effect transistor，MISFET) 30,其源極與沒極分別連接於二像素電極12，如第3 (b)圖所示， 而基底偏壓係由透明電極16提供至ρ型層22，而具有閘極電容 Csub之接地矽基底則被視為假想mjSFET裝置3〇的閘極。 1325634 由於電谷元件在實際結構上的高寬比之影響，若與電容c】或 Q相比較’電容cpd以及csub值不夠大，因此在相麟素電極12 之間的電位分佈很容易因橫向二維效應而被偏壓所控制，該偏壓 係接近於施加在⑽像素電極12 ±的電驗應賴值。所以覆置 mISFET3()的通道電位會藉由像素電極12經電容Cl以及Q之輕 合而拉高許多，而電容Cpd4 Csub並無法使像素電極間隙區域維持 錄低電位。電子曝電電位轉高度會低於-維接近阻障 高度，產生跨越干擾電流跨躍相鄰之像素，如第4圖所示。 、第5圖為第3 (a)圖所示裝置結構之像素電極以及電極間隙區 域的垂直此帶® ’其中該電極_表示相鄰像素電極Η的間隙， 而電子通道層係位於本徵層2G與n型層18的介面。由於本徵層 20以及η型層18的材料具有不同的能量導電帶高度，形成了異質 接面⑽ro:j_ion)帶，因此大部分電子會聚集積存此介面處， =電子通道層’而光致電子則會流過η型層Μ導電帶至像素電 ΓΓΓ—方面’本徵層2G與η型層18介㈣會形成跨越相鄰 電極12的水平載子而造成如第3⑷_第4圖中所解釋的 3干^題。再者，像素電極間隙區域的電位阻障會如第4、5 ===阻障高度降低。以第3⑴圖所假想之娜㈣An image sensor such as a semiconductors' CMOS or a charge coupled device (CCD) is a germanium semiconductor device designed to capture photons (light rays) and convert photons into electrons. After being converted into an electron, the electron is transmitted and converted again into a measurable voltage, which is converted into digital data. The industry has studied the imaging system based on hydrogenated amorphous silicon (a-Si:H) stacked on a CCD or CMOS device to pursue a sensor that is superior to conventional CCD or CMOS image sensors. Performance, as described below. The high-light-collecting effective area ratio (flll fact〇r) caused by the stacked structure enables the entire pixel area to be used to sense photons, and to convert the a_Si:H material to effectively convert energy, thereby achieving high quantum efficiency. . However, in known studies, such sensors still have problems such as _-talk, imagelag, and leakage current signals. The problem that the carrier crosses the adjacent pixels in particular causes a serious problem of insufficient resolution and uniformity, which also causes color crosstalk between pixels, resulting in color distortion. In addition, the deep trap or field emission transport mechanism in the superior material causes a low carrier movement rate, which is prone to image defects, thus producing a bright spot afterimage in the moving image. Specialist 5 1325634 Since all the signals of a pixel cannot be read in a single facet, it is impossible to reproduce the true color in the low signal level when the image delay problem occurs. Furthermore, the problem of "electricity" is mainly due to the fact that the light-guide layer towel is injected into the hole from the metal electrode to the p-layer or the n-layer (n layer). It will be very strange in the dark curtain. Therefore, in order to compete with traditional 矽-based CCD or CM〇s image sensing, the above three main problems need to be solved to provide better kneading quality. The following materials have been developed for the purpose of cutting a-Si:H materials: () Transparent conductive layers, materials such as Indium Tin Oxide (ITO;); (B) Boron heavily doped p-type The layer comprises a hydrogenated amorphous ruthenium carbide (10), which is used to collect the photo-induced hole generated in the intrinsic layer (intrinsie layCT, i_laye〇 to ITO; a-Si:H intrinsic layer, mainly as a photoelectron_hole pair generating layer; (iv) a scaled (phosphorus) heavily doped n-type layer containing hydrogenated carbon doped amorphous germanium (hydrogenated carbon doped surface) The twitch is still silic〇n) the material is received by the electrons generated from the intrinsic layer for transmission to the gold hybrid electrode; and (5) the metal pixel electrode is disposed under the n-type layer and connected to the transistor, Vertically stacked above the 2CM〇s circuit on the germanium substrate. Figure 8 shows the energy band diagram of a p_i-n heterojunction with an intrinsic/n-type layer junction. The charge-to-voltage conversion rate is mainly determined by _ The size of the capacitor, and ^ is minimized by thickening the intrinsic layer. ' 1325634 In the a-Si:H intrinsic layer to achieve higher quantum efficiency, it is necessary to produce a longer-lived minority carrier (min〇rit^ earner) and a higher load in a larger thickness by optimizing the concentration of hydrogen atoms. Sub-mobility to improve photoconductivity and light absorption. Meanwhile, the boron heavily doped p-type layer under the ιτο layer can be replaced by a methyl a_Sic.H (based a-SiC:H) layer to form a-Si: The H intrinsic layer forms a heterojunction. Since the tantalum carbide has a large optical energy gap 〇argeropticaI bandgap, E〇pt), it can effectively enhance its transparency, and can also prevent leakage current by expanding the band gap, thereby avoiding The electrons are diverged from the I 〇 layer to the p-type layer due to the puncturing effect. Furthermore, the (xS^CH material can also be applied to the n-type layer to reduce the cross-talk between the pixel electrodes by reducing the conductivity of the n-type layer between the pixel electrodes. (4) This design can also effectively block the hole. It is diffused from the titanium nitride (TiN) pixel electrode to the n-type layer, which is the same as the case where the electron is punctured to the p-type layer. However, the high-density ice de-rubber of the α·% material causes leakage. Problems such as current and image delay. ^ Furthermore, a more serious problem occurs at the intersection of the corners of the pixel electrode and the layer of the layer. [The line is bent due to the local electric field strength, as shown in Fig. 2. At the edge of the heart, the probability of migration caused by the wear of the towel will become larger, and then the reverse bias [jf-shaped leakage current. In addition, the self-constituted n-type layer will also effectively adhere to the TlN pixel electrode. On the top, without peeling off (peeiing_〇tf), p; tension relationship 'the α-SiC film pressed on the corners of the pixel electrode may be high in degree, causing the same as the image delay Pixel defects, as shown in Figure 2. 132 please refer to the 3rd (a) to 4th There are pin sound male Nie Wei Shaodan I#, middle 3 (a) is the equivalent circuit diagram of the image sensor shown in the figure ==, and = =::: is set on a base (not shown), on a plurality of pixels = and on the oxygen-cut insulating layer 24, the light-guiding layer 14 is disposed on the photoconductive layer 14 on the image of the second layer and the light-transmissive layer 16, wherein the light-guide layer is contained below An n-type layer 18, an intrinsic layer 20, and a p-type layer 22 form a so-called stacked p_i-n layer structure.乂 > The photoconductive layer 14 is described below with Cpd, Csub, C] and c2Eg capacitive elements. These capacitors 7L are positioned with a point at which the n-type layer/intrinsic layer interface is located at the center of the gap of the pixel electrode 12 as shown in Fig. 3(a). Here, c(d) represents a capacitive element of a transparent electrode 形成 formed by oxidizing a sulphur tin (5) 1 thief such as • 'IT ,, and Csub denotes a p-type 矽 substrate (not shown). The capacitive element of the oxidized oxide layer 24 is & and q represent the capacitive elements of the adjacent metal pixel electrodes 12, respectively. The device structure of the conventional image sensor can be assumed to be a flipped metal insulator semiconductor field effect transistor (MISFET) 30, and the source and the gate are respectively connected to the second The pixel electrode 12 is as shown in FIG. 3(b), and the substrate bias is supplied from the transparent electrode 16 to the p-type layer 22, and the ground germanium substrate having the gate capacitance Csub is regarded as the imaginary mjSFET device. Gate. 1325634 Due to the influence of the aspect ratio of the electric grid element on the actual structure, if the capacitance cpd and the csub value are not large enough compared with the capacitance c or Q, the potential distribution between the phase electrodes 12 is easily due to the lateral direction. The two-dimensional effect is controlled by a bias that is close to the value of the test applied to the (10) pixel electrode 12 ±. Therefore, the channel potential of the mISFET 3 () is raised by the pixel electrode 12 via the junctions of the capacitors C1 and Q, and the capacitor Cpd4 Csub does not maintain the pixel electrode gap region at a low potential. The electronic exposure potential transition height will be lower than the -dimensional proximity barrier height, resulting in a span of adjacent pixels across the interference current, as shown in Figure 4. Figure 5 is the pixel electrode of the device structure shown in Figure 3 (a) and the vertical gap of the electrode gap region. 'The electrode_ represents the gap between adjacent pixel electrodes, and the electron channel layer is located in the intrinsic layer. The interface between the 2G and n-type layers 18. Since the materials of the intrinsic layer 20 and the n-type layer 18 have different energy conduction band heights, a heterojunction (10) ro:j_ion) band is formed, so most electrons are accumulated and accumulated at the interface, and the electron channel layer is The electrons will flow through the n-type layer of the germanium conduction band to the pixel electrode. The 'intrinsic layer 2G and the n-type layer 18 (4) will form a horizontal carrier across the adjacent electrode 12, resulting in the third (4)_4th picture. The three questions explained. Furthermore, the potential barrier of the pixel electrode gap region is lowered as in the fourth, fifth === barrier height. Imagined by the 3rd (1) figure (4)
強積體效i α Π⑽2G或在像素％極12提供高壓以藉由增 爾感祕色料咖㈣物W嫌牲，而L 1325634 素電極電壓並不能滿足電源供應之電性規格要求。 【發明内容】 因此本發明之主要目的在於提供一種影像感測器及其至作方 法’以解決上述習知影像感測器的問題。 根據本發明之申請專利範圍，本發明一種影像感測器，其包含 有一半導體基底以及包含定義於該基底上之複數個像素的一像素 矩陣。影像感測器另包含一光導層以及一透明導電層依序設於個 像素的像素電極之上，以及包含-遮蔽·，設於任二相鄰之像 素電極’且呈一網狀物排列於各像素電極外圍。 根據本發明之申請專利範圍，另揭露一種製作一影像感測器之 方法，首先提供-基底’該基底包含複數個像素以及複數個像素 電路設於其表面。然後於該基底上形成—導電層，進行一第一微 • 影暨蝕刻製程（Ph0碰h〇gmphy-etching p職ss，PEP)以移除部 分該導，而於各像素中形成-像素電極以及於任二相鄰像素 電極之間形成-遮蔽電極^之後於像素電極以及遮蔽電極上形成 一光導層，並形成一透明導電層覆蓋該光導層。 由於本發明之遮蔽電極係形成於像素電極之間，所以可以防止 發生載子跨針擾。·，光料的本徵層可明厚而得到良好 的影像感測器敏感度。 1325634 【實施方式】 請參考第6圖至第7圖，其中第6圖為本發明一影像感測器1〇〇 的剖面示意圖，而第7圖為第6圖所示部分影像感測器1〇〇的上 視圖。影像感測器100係為一光導體覆主動像素 (photoconductor-on-active-pixel，POAP)影像感測器，其係形成 於包含一基底104之一半導體晶片102上。影像感測器100包含 有設於基底104上之一介電層106以及複數個像素1〇8定義於基 底104上，其中像素108係排列成一像素矩陣11〇,如第7圖所示。 每一像素108包含設於介電層1〇6中之一像素電路112以及一像 素電極114’其中像素電路112可包含至少一金屬氧化物場效應電 晶體（metal-oxide-semiconductor filed effect transistor，M0SFET)， 而像素電極114則包含金屬材料，例如氮化鈦咖如， ΤιΝ)，並經由接觸插塞136而垂直電連接其對應之像素電路Η〗。 在不同的巾’像素電極114還可包含其他導電材料，例如 鎮（tungsten ’ (ahmlinum，A1)或銅（⑺卿，a)。此 外’相鄰像錢極114的邊緣之間具有一像素間隙區域（細她 gap region ) G ° 处蚁电極U6係設於電極間隙區域^中，並 她丨U之間。所以，遮蔽電極116係排列如二 奸環繞各像素電極114外圍，如第7 _示。在較 & , 魏電極116係設置於電極間隙區域G的中央部分 114與遮蔽電極116具有相同的距離d，且遮敍 財作相鄰像素108的分界線。再者，遮蔽 ‘、、 :::二 114具！^同的材料，例如TiN，也可利用同樣的製: 地電严14 —併製作^成。於遮㈣極π6上可提供一接 提’错由觸__11G賴之—冑健應電路所 =叫綱物輯極110並沒輸流過。在此處， 二間=====很重要的角色’其能藉由降低接近像素 ，門隙£域G表面的電位而電性隔離相鄰的像素⑽， 景^像感測ϋ結構在像素之_具錄大的雜效應（㈣㈣ effect) ’因而造成跨越干擾電流。 根據本發明，一絕緣層⑽係設置於介電層觸、遮蔽電極116 ，及像素電極m之上。絕緣層118可為—薄氧化層（例如為二 乳化石夕’ Silicon oxide，Si〇2)，其僅僅覆蓋像素電極114之邊緣而 暴露出像素電極m的大部分中央區域，使得像素電極114直接 電連接於其上方的光導層120。 影像感測器100另包含一光導層120以及一透明導電層122覆 盍於絕緣層118以及像素電極114上。光導層12〇由下至上包含 一 η型層130、一本徵層132以及一 P型層134。其中，本徵層132 係由a>*Sl:H材料所構成，而p型層134以及n型層130包含a_SiC:H 材料。為了提供良好的影像感測器1〇〇敏感度與色彩平衡，本徵 曰32必/員有足夠的厚度η，且厚度η可為約5〇〇〇埃或大於5〇〇〇 1325634 埃。透明導電層I22係用來當作一上電極板，可由氧化銦錫（indium tin oxide，ΐτο)所構成。此外，影像感測器1〇〇可包含一第一平 坦層124、一彩色濾光層126以及一第二平坦層128依序設於光導 層120之上，其中彩色濾光層126於不同像素1〇8中可包含不同 顏色的彩色濾光片，例如紅色、綠色以及藍色等彩色濾光片。 本發明所提供的功效可藉由第6圖所示之一等效電路來解 釋。以本徵層132與η型層130介面之電極間隙區域G中央節點 來考量，Csub表示遮蔽電極116電容，Cpd代表透明電極（ΙΤ〇)122 的電容，而c】以及a則分別代表相鄰金屬像素電極114的電容。 因此’Csub會變得比沒有遮蔽電極116的傳統影像感測器者大上許 多。所以，遮蔽電極116能有力地使表面電位維持至一低電位， 且像素電極間隙區域G之中具有-維阻障高度，能防止第4圖傳 統影像感測器載子在相鄰像素間跨越干擾之問題。 第8圖為第6圖所示影像感測器100之相鄰像素電極114以及 遮蔽電極116的能帶圖。由於遮蔽電極116下的電位會因薄絕緣 層118與η型層130轉持在—低電位’很鴨地，在電極間隙 區域G之内的本徵層132與η型層13G介面間發生的跨越干擾效 應會因高電位阻障高度（例如第8圖所示之-維阻障高度）而被 中斷。此作肢得縣徵層132可被應本發明結構中，並以 現存的偏壓條件即可增強量子效率。 1325634 另方面於遮蔽電極Π6上之薄絕緣層ns的厚度可根據 本徵層132以及η麵13〇間介面之電位來決定，其中較佳藉由 調整絕緣層118之厚度以最大化_電容I)。此外，貌絕 緣層】18厚度的另一原則係為了保護像素電極114的邊緣轉角， 以避免因射電場而造成的異常電洞遂穿，導致發生漏電流情 形。再者’舰緣層！18亦有助於防止因張力麗力而造成η型層 130之中的深陷情形’其會帶來影像延遲問題。請參考第7圖，遮 蔽電極116以及像素電極114的邊緣部分皆被絕緣層u8所覆蓋， 因此在η 13G以及像素電極114的接觸區域上將不再有強大 的電场與拉力壓力，所以本發明影像感測器觀結構消除了造成 像素電極114邊角處漏電流問題的基本成因。 第9圖為第3 (a)圖所示習知影像感測器1〇結構具有厚度分 別為5000埃、7_埃以及刪〇埃之本徵層2〇的電位圖表。如 第9圖所示，兩相鄰之像素電極12分別具有電位，The strong body effect i α Π (10) 2G or the high voltage at the pixel % pole 12 is provided by the illuminating color, and the L 1325634 element electrode voltage does not meet the electrical specifications of the power supply. SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide an image sensor and method for the same thereof to solve the problems of the conventional image sensor described above. In accordance with the scope of the present invention, an image sensor of the present invention includes a semiconductor substrate and a pixel matrix including a plurality of pixels defined on the substrate. The image sensor further includes a light guiding layer and a transparent conductive layer sequentially disposed on the pixel electrodes of the pixels, and the inclusion-shading layer is disposed on any two adjacent pixel electrodes and arranged in a mesh The periphery of each pixel electrode. In accordance with the scope of the present invention, a method of fabricating an image sensor is disclosed, first providing a substrate comprising a plurality of pixels and a plurality of pixel circuits disposed on a surface thereof. Then forming a conductive layer on the substrate, performing a first micro-shading and etching process (Ph0), removing a portion of the conductive, and forming a pixel electrode in each pixel. And forming a light guiding layer on the pixel electrode and the shielding electrode after forming a shielding electrode between any two adjacent pixel electrodes, and forming a transparent conductive layer to cover the light guiding layer. Since the shield electrode of the present invention is formed between the pixel electrodes, it is possible to prevent the occurrence of carrier crosstalk. · The intrinsic layer of the light material can be brightened to obtain good image sensor sensitivity. 1325634 [Embodiment] Please refer to FIG. 6 to FIG. 7 , wherein FIG. 6 is a cross-sectional view of an image sensor 1 为本 of the present invention, and FIG. 7 is a partial image sensor 1 shown in FIG. 6 . The top view of the cockroach. The image sensor 100 is a photoconductor-on-active-pixel (POAP) image sensor formed on a semiconductor wafer 102 including a substrate 104. The image sensor 100 includes a dielectric layer 106 disposed on the substrate 104 and a plurality of pixels 〇8 defined on the substrate 104. The pixels 108 are arranged in a matrix of pixels 11 as shown in FIG. Each of the pixels 108 includes a pixel circuit 112 disposed in the dielectric layer 〇6 and a pixel electrode 114'. The pixel circuit 112 may include at least one metal-oxide-semiconductor filed effect transistor (metal-oxide-semiconductor filed effect transistor). The PMOS electrode 114 includes a metal material such as titanium nitride, and is electrically connected to its corresponding pixel circuit via the contact plug 136. The pixel electrode 114 may also comprise other conductive materials in different towels, such as tungsten ' (ahmlinum, A1) or copper ((7), a). In addition, there is a pixel gap between the edges of the adjacent image poles 114. The area (fine gap region) G ° ant electrode U6 is placed in the electrode gap area ^, and her 丨 U. Therefore, the shielding electrode 116 is arranged around the periphery of each pixel electrode 114, such as the seventh In the &, the central portion 114 of the Wei electrode 116 disposed in the electrode gap region G has the same distance d as the shield electrode 116, and covers the boundary line of the adjacent pixel 108. Further, the masking ' , ::: two 114! ^ The same material, such as TiN, can also use the same system: the ground electricity is strict 14 - and made ^ into. On the cover (four) pole π6 can provide a pick up 'wrong touch _ _11G Laizhi-胄健应电路==The class of the program is 110 and has not been transmitted. Here, the two ===== very important role's can reduce the proximity to the pixel, the gate gap The potential of the G surface is electrically isolated from adjacent pixels (10), and the image sensing ϋ structure has a large impurity effect in the pixel ( (4) (4) effect) 'Therefore creating an interference current. According to the present invention, an insulating layer (10) is disposed over the dielectric layer, the shielding electrode 116, and the pixel electrode m. The insulating layer 118 may be a thin oxide layer (for example, two Epoxy silicon oxide, Si〇2), which covers only the edge of the pixel electrode 114 to expose most of the central region of the pixel electrode m, so that the pixel electrode 114 is directly electrically connected to the photoconductive layer 120 above it. The device 100 further includes a light guiding layer 120 and a transparent conductive layer 122 overlying the insulating layer 118 and the pixel electrode 114. The light guiding layer 12 includes an n-type layer 130, an intrinsic layer 132 and a p-type layer from bottom to top. 134. wherein the intrinsic layer 132 is composed of a>*Sl:H material, and the p-type layer 134 and the n-type layer 130 comprise a_SiC:H material. In order to provide good image sensor sensitivity and The color balance, the intrinsic 曰32 must have a sufficient thickness η, and the thickness η can be about 5 〇〇〇 or more than 5 〇〇〇 1325634 Å. The transparent conductive layer I22 is used as an upper electrode plate. Can be indium tin oxide (ΐτο) In addition, the image sensor 1A may include a first planar layer 124, a color filter layer 126, and a second planar layer 128 disposed on the photoconductive layer 120, wherein the color filter layer 126 is Color filters of different colors may be included in different pixels 1〇8, such as color filters such as red, green, and blue. The effects provided by the present invention can be explained by an equivalent circuit shown in FIG. Considering the central node of the electrode gap region G of the intrinsic layer 132 and the n-type layer 130 interface, Csub represents the capacitance of the shielding electrode 116, Cpd represents the capacitance of the transparent electrode (ΙΤ〇) 122, and c] and a represent the phase respectively. The capacitance of the adjacent metal pixel electrode 114. Therefore, 'Csub will become much larger than the conventional image sensor without the shield electrode 116. Therefore, the shielding electrode 116 can strongly maintain the surface potential to a low potential, and the pixel electrode gap region G has a -dimensional barrier height, which can prevent the conventional image sensor carrier of FIG. 4 from crossing between adjacent pixels. The problem of interference. Fig. 8 is an energy band diagram of the adjacent pixel electrode 114 and the shielding electrode 116 of the image sensor 100 shown in Fig. 6. Since the potential under the shielding electrode 116 is caused by the thin insulating layer 118 and the n-type layer 130 being held at a low potential 'very duck ground, occurs between the intrinsic layer 132 and the n-type layer 13G interface within the electrode gap region G. The cross-interference effect is interrupted by the high potential barrier height (eg, the height of the barrier barrier shown in Figure 8). This vestige 132 can be used in the structure of the present invention to enhance quantum efficiency under existing bias conditions. 1325634 The thickness of the thin insulating layer ns on the shielding electrode Π6 can be determined according to the potential of the intrinsic layer 132 and the interplanar interface of the n-plane 13 , wherein the thickness of the insulating layer 118 is preferably adjusted to maximize the _capacitance I. ). In addition, another principle of the thickness of the 18-layer thickness is to protect the edge angle of the pixel electrode 114 to avoid abnormal hole tunneling due to the electric field, resulting in leakage current. Again, the ship's edge! 18 also helps to prevent deep trapping in the n-type layer 130 due to tension Lili, which causes image delay problems. Referring to FIG. 7, the edge portions of the shielding electrode 116 and the pixel electrode 114 are covered by the insulating layer u8, so that there is no strong electric field and tensile force on the contact region of the η 13G and the pixel electrode 114, so The invention of the image sensor structure eliminates the basic cause of leakage current problems at the corners of the pixel electrode 114. Fig. 9 is a graph showing the potential of the conventional image sensor 1〇 structure shown in Fig. 3(a) having thicknesses of 5000 Å, 7 Å, and intrinsic layer 2 〇. As shown in Fig. 9, the two adjacent pixel electrodes 12 have potentials, respectively.
而二像素電極12之__區_不具有電位轉高度或僅有很 小的電位轉磁。所以’在本徵層2G巾產生的電子很容易由右 =高電位的像素電極12移_左側低電位的像素電極12，造成 ?越干擾問題。相反的’第1Q圖為第6圖所示本發明影像感測器 _之本縣132厚度為觸埃、7GGG埃錢1GGGG埃的電位圖。 如第ίο圖所示’二相鄰像素電極m分別具有12乂卩及2奶之 電位，而像素電極114之間的間隙區域G則具有—很大的阻障高 度。所以由具有電位差的二相鄰像素電極114所產生的橫向電場 1325634 並不會太大，且本發明影像感測器100的遮蔽電極116在相鄰二 像素電極114之間產生了很大的電位阻障高度，以有效避免跨越 干擾問題。因此，具有大於5000A之厚度的本徵層132可應用於 本發明影像感測器100中。 請參考第11圖至第15圖，第11圖至第15圖為本發明影像感 測器1〇〇的製程示意圖。首先，如第n圖所示，提供一半導體晶 片102，其包含有一矽基底丨04。接著，於基底1〇4上提供複數個 電子元件，以形成像素電路112設於介電層106中。接著，於介 電層106上形成一導電層138，位於像素電路112之上。導電層 可包含金屬材料，較佳為TiN，且具有約3〇〇埃之厚度。請參 考第12圖，接著進行一微影暨蝕刻製程’以移除部分導電層 而於各像素1G8中形成-像素電極114,同時於像素電極ιΐ4之間 形成-遮蔽電極116。因此，遮蔽電極116與像素電極ιΐ4係設於 同一平面上。再者，遮蔽電極116至鄰近像素電極ιΐ4皆具=相 同的距離。在本發明中，遮蔽電極116的寬度為約G2微 (職職伽，_)，而與鄰近之各像素電極m的距離為約⑽ 接著，於基底祕上形成一薄絕緣層118 以及遮蔽電極116，如第13圖所示。絕緣層⑽ /、H14 例如氧切，且厚度為約埃。請參考第Μ圖=絕=料， 暨钕刻製程，以移除部分絕緣層m並暴露_分== 15 】14，然而像素電極114的邊 緣層丨丨8所覆蓋。然後，於遮蔽電極丨丨6則仍然被絕 型層丨3〇、-《細構成之树作一 Μ咖構成之" 一層⑶，其;二二 厚声PM 具有㈣埃之 二Γ ΓΓ為物0埃，而η型層130之厚度為約 考於光^層120上形成一透明導電層122。然後，在 以層122上依序形成—第一平坦層124、-彩色濾光層126 ^ '一平坦層128以完成本發明影像感測器1〇〇之製作，如 第丨5圖所示。 相較於習知技術’本發明提供一影像感測器結構，其在相鄰像 素電極之間具有高電位阻障，以避免跨越干擾之情形。再者，覆 蓋於遮蔽電極以及像素電極之邊緣部分的絕緣層能避免遂穿效 鲁 應，以改善影像延遲以及漏電流問題。所以，本發明能提供具有 良好衫像效果與功能的影像感測器。 以上所述僅為本發明之較佳實施例，凡依本發明申請專利範 圍所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 16 【圖式簡單說明】 第1圖為一具a_SlC:H (p型層)八猶(本徵層)八H (n型層）接合之ρ-ί·η異質接面的能帶圖。 f2圖為像素電極邊緣部分之張力以及遂穿問題的示意圖。 弟3 (a)圖係聰。—具有p+n層堆疊結構之影像感測 側剖面示意圖。 ^ 3 (b)圖為第3⑷_示之影像感測⑽等效電路圖。 同__ f電極與電極間隙的能帶示意圖。 域的垂直=圖所示裝置結構之像素電 第6圖為本發明一影像感測器的剖面示意圖。 第7圖為第6圖所示本發明影像感測器的上視圖。 第8圖為第6圖所示本發明影像感測器的能帶圖。 第9圖為第3⑷圖所示習知影像感測器結構的電位圖表。 第10圖為第6圖所示本發明影像感測器的電位圖表。 第11圖至第15圖為本發明影像❹指的製程示意圖。 【主要元件符號說明】 10 影像感測器 12 像素電極 14 光導層 16 逯明電極 18 η型層 20 本徵層 22 Ρ型層 24 Ί缘膜 30 MISFET 100 影像感測器 17 半導體晶片 104 基底 介電層 108 像素 像素矩陣 112 像素電路 像素電極 116 遮蔽電極 絕緣層 120 光導層 透明導電層 124 第一平坦層 彩色濾光層 128 第二平坦層 η型層 132 本徵層 ρ型層 136 接觸插塞 導電層The __region_ of the two-pixel electrode 12 does not have a potential turn height or only a small potential turn. Therefore, the electrons generated in the intrinsic layer 2G towel are easily moved by the right-high potential pixel electrode 12 to the left-side low-potential pixel electrode 12, causing a problem of interference. The opposite '1Q' is the potential map of the county 132 of the image sensor of the present invention shown in Fig. 6, which is the thickness of the touch, 7GGG, and 1GGGG. As shown in Fig. ί, the two adjacent pixel electrodes m have potentials of 12 Å and 2 mils, respectively, and the gap region G between the pixel electrodes 114 has a large barrier height. Therefore, the lateral electric field 1325634 generated by the two adjacent pixel electrodes 114 having the potential difference is not too large, and the shielding electrode 116 of the image sensor 100 of the present invention generates a large potential between the adjacent two pixel electrodes 114. The height of the barrier is to avoid cross-interference problems. Therefore, the intrinsic layer 132 having a thickness greater than 5000 Å can be applied to the image sensor 100 of the present invention. Please refer to Fig. 11 to Fig. 15, and Fig. 11 to Fig. 15 are schematic diagrams showing the process of the image sensor 1 of the present invention. First, as shown in Fig. n, a semiconductor wafer 102 is provided which includes a germanium substrate 04. Next, a plurality of electronic components are provided on the substrate 1 to form the pixel circuit 112 in the dielectric layer 106. Next, a conductive layer 138 is formed on the dielectric layer 106 over the pixel circuit 112. The conductive layer may comprise a metallic material, preferably TiN, and has a thickness of about 3 angstroms. Referring to Fig. 12, a lithography and etching process is then performed to remove a portion of the conductive layer to form a pixel electrode 114 in each of the pixels 1G8, and a mask electrode 116 is formed between the pixel electrodes ι4. Therefore, the shielding electrode 116 and the pixel electrode ι4 are disposed on the same plane. Furthermore, the shielding electrode 116 to the adjacent pixel electrode ι4 have the same distance. In the present invention, the width of the shielding electrode 116 is about G2 micro (career gamma, _), and the distance from the adjacent pixel electrode m is about (10). Next, a thin insulating layer 118 and a shielding electrode are formed on the substrate. 116, as shown in Figure 13. The insulating layer (10) /, H14 is, for example, oxygen cut, and has a thickness of about angstrom. Please refer to the figure 绝 绝 绝 绝 绝 , , , , , , , , , 移除 移除 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分 部分Then, the shielding electrode 丨丨6 is still surrounded by the absolute layer 丨3〇, - "The thinly constructed tree is made up of a café" (1), and the second and second thick sound PM has (4) 埃之二Γ ΓΓ The material is 0 angstroms, and the thickness of the n-type layer 130 is about to form a transparent conductive layer 122 on the optical layer 120. Then, a first flat layer 124, a color filter layer 126 ^ 'a flat layer 128 are sequentially formed on the layer 122 to complete the fabrication of the image sensor 1 of the present invention, as shown in FIG. . In contrast to the prior art, the present invention provides an image sensor structure having a high potential barrier between adjacent pixel electrodes to avoid crosstalk. Furthermore, the insulating layer covering the shielding electrode and the edge portion of the pixel electrode can avoid the effect of squeezing to improve image delay and leakage current. Therefore, the present invention can provide an image sensor having a good shirt image effect and function. The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should fall within the scope of the present invention. 16 [Simple description of the diagram] Figure 1 is an energy band diagram of a ρ-ί·η heterojunction with a_SlC:H (p-type layer) eight-seven (intrinsic layer) eight H (n-type layer) junction. The f2 diagram is a schematic diagram of the tension of the edge portion of the pixel electrode and the problem of the tunneling. Brother 3 (a) Tu Cong. - Image sensing side profile with p+n layer stack structure. ^ 3 (b) The figure is the image sensing (10) equivalent circuit diagram shown in 3(4)_. Schematic diagram of the energy band with the __f electrode and electrode gap. Vertical of the domain = pixel of the device structure shown in the figure Fig. 6 is a schematic cross-sectional view of an image sensor of the present invention. Fig. 7 is a top view of the image sensor of the present invention shown in Fig. 6. Figure 8 is an energy band diagram of the image sensor of the present invention shown in Figure 6. Fig. 9 is a potential diagram of a conventional image sensor structure shown in Fig. 3(4). Fig. 10 is a graph showing the potential of the image sensor of the present invention shown in Fig. 6. 11 to 15 are schematic views showing the process of the image finger of the present invention. [Main component symbol description] 10 Image sensor 12 Pixel electrode 14 Photoconductive layer 16 电极 electrode 18 η-type layer 20 Intrinsic layer 22 Ρ-type layer 24 Ί edge film 30 MISFET 100 image sensor 17 semiconductor wafer 104 substrate Electrical layer 108 pixel pixel matrix 112 pixel circuit pixel electrode 116 shielding electrode insulating layer 120 photoconductive layer transparent conductive layer 124 first flat layer color filter layer 128 second flat layer n-type layer 132 intrinsic layer p-type layer 136 contact plug Conductive layer