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3> 7補惠 A7 B7 經濟部中央標隼局員工消費合作杜印製 五、發明説明（ί ) - 發明背景 在非揮發性記憶體兀件(Nonvolatile Memory Device) 中’複晶矽氧化膜(Polyoxide)是不可缺少的介電材料。爲 了保持記憶體元件儲存資料的可靠性，此介電材料必須具 有低漏電流及咼崩潰電場等特性。而這些特性又與氧化膜 /複晶矽之界面平坦程度有密切的關係。一般而言，愈平 坦的界面會有較佳的低漏電流及高崩潰電場等特性。 傳統非揮發性記憶體元件的製作過程，是採用高溫爐 或快速熱氧化(Rapid Thermal Oxidation ; RTO)將複晶矽表 面直接高溫氧化成長一層複晶矽氧化膜。由於複晶矽具有 晶粒(Grain)構造，晶粒間存有晶粒界爾Grain Boundary)。 —般複晶矽在高溫氧化時，晶粒界面的矽氧化速率遠大於 在晶粒底材(Bulk)的矽氧化速率。因此以高溫氧化方法成 長複晶矽氧化膜時，易使氧化膜/複晶矽界面變的相當粗 糙，致使複晶矽氧化膜的介電特性變差，導致高漏電流及 低崩潰電場。 本發明提供一種以陽極氧化法來成長複晶矽氧化膜之 技術，即將複晶矽置於電解溶液中並接上陽極，由陽極提 供電壓或電流促使複晶矽表面發生氧化反應形成氧化膜。 該氧化膜可應用於上述非揮發性記憶體元件。陽極氧化法 所成長之複晶矽氧化膜，不但具有平坦的氧化膜/複晶矽 界面，且該陽極氧化法可以在室溫下進行，製程簡單、容 易操作'又低成本。所形成的複晶矽氧化膜經過最佳化熱 處理後，具有非常優越電性上、信賴性上的特性’足可提 本紙張尺度適用中國國家椟準（CNS ) Α4規格（210Χ297公釐.) (請先閱讀背面之注意事項再填寫本頁) 派·3 > 7 Complementary benefits A7 B7 Printed by the staff of the Central Bureau of Standards of the Ministry of Economic Affairs of the People's Republic of China 5. Production Description (ί)-Background of the Invention In the nonvolatile memory device (Nonvolatile Memory Device) Polyoxide) is an indispensable dielectric material. In order to maintain the reliability of the data stored in the memory element, the dielectric material must have characteristics such as low leakage current and high breakdown electric field. These characteristics are closely related to the flatness of the oxide / polycrystalline silicon interface. Generally speaking, flatter interfaces have better characteristics such as low leakage current and high breakdown electric field. The traditional non-volatile memory device is manufactured by using a high temperature furnace or Rapid Thermal Oxidation (RTO) to directly oxidize the surface of the polycrystalline silicon to a layer of polycrystalline silicon oxide film. Since polycrystalline silicon has a grain structure, Grain Boundary exists between the grains. —When polycrystalline silicon is oxidized at high temperature, the silicon oxidation rate at the grain interface is much higher than that at the grain substrate (Bulk). Therefore, when growing a polycrystalline silicon oxide film by a high temperature oxidation method, it is easy to make the oxide film / polycrystalline silicon interface relatively rough, which causes the dielectric characteristics of the polycrystalline silicon oxide film to deteriorate, resulting in high leakage current and low breakdown electric field. The present invention provides a technology for growing a polycrystalline silicon oxide film by anodic oxidation. That is, the polycrystalline silicon is placed in an electrolytic solution and connected to an anode. The anode provides a voltage or current to promote the oxidation reaction on the surface of the polycrystalline silicon to form an oxide film. The oxide film can be applied to the non-volatile memory element. The anodized polycrystalline silicon oxide film not only has a flat oxide film / polycrystalline silicon interface, but also can be performed at room temperature. The process is simple, easy to operate, and low cost. The formed polycrystalline silicon oxide film has excellent electrical and reliability characteristics after optimized heat treatment. It is sufficient to mention that the paper size is applicable to China National Standard (CNS) A4 specification (210 × 297 mm.) (Please read the notes on the back before filling out this page)
、1T 經濟部中央標準局員工消費合作社印製 ι〇 95 3 7, 1T Printed by the Consumer Cooperatives of the Central Bureau of Standards, Ministry of Economic Affairs ι〇 95 3 7
五 '發明説明（2J 供應用於非揮發性記憶元件製作技術上。 ~ 發明槪述 本發明揭示一種複晶矽氧化膜，其特徵在於該複晶矽 氧化膜係藉陽極氧化法形成。 本發明另揭示以陽極氧化法成長複晶矽氧化膜，經由 快速退火最佳化處理，可以提升複晶矽氧化膜之品質。 經實驗上證明，此種方法所形成的複晶矽氧化膜比傳 統高溫爐或快速熱氧化成長的複晶矽氧化膜具有更平坦的 介面，更優越的電特性及信賴性。因此，利用陽極氧化法 在複晶矽上成長氧化膜，對於強化非揮發性記憶體元件的 儲存資料能力有極大的改善。 發明的詳細說明 本發明提供一種利用陽極氧化法在室溫下成長高品質 、複晶矽氧化膜，應用於非揮發性記憶體元件。 以陽極氧化法成長之複晶矽氧化膜實質上爲非多孔 性、無殘留雜質、及表面平坦之氧化膜。爲了測試其電特 性，分別準備陽極氧化法成長之複晶矽氧化膜、及快速熱 氧化之複晶矽氧化膜，製作複晶矽-氧化膜-複晶矽 (Polysilicon-Polyoxide-Polysilicon)電容器。該等複晶砂氧化 膜的厚度均爲70埃。 本發明之具體實施例將參照圖1(a)至圖1(g)被描述如 下。 -4- H I In I— HI 1 n ^ n 1 n ί 丁 Ϊ 3, Ί (請先閱讀背面之注意事項再填寫本頁) 本紙張尺度適用中國國家標準（CNS ) Α4规格（210X297公釐） 0 9 5 3 7 A7 : __·_B7____ _ 五、發明説明（3) 圖1(a)，矽晶片10經RCA標準淸洗製程處理過後， 先在砂晶片10表面，以高溫爐成長一層厚度1000埃的二 氧化砂層20 〇 圖1(b)，利用低壓化學氣相沉積法，沉積一層厚度3 5〇〇 埃摻雜磷之第1複晶矽層30。 圖1(c)，再經過一次RCA標準淸洗製程處理後’將矽 晶片放入電解溶液(0.01%檸檬酸溶液)中，23°C下並將摻 雜磷之第1複晶矽層30接上陽極，通定電壓(35伏特)3分 鐘，來使摻雜磷之第1複晶矽層表面發生氧化反應生成複 晶矽氧化膜40。此複晶矽氧化膜(約厚70埃)再經過快速退 火處理，於N2氣體中850°C下，退火處理30秒，將氧化 膜/複晶矽界面未鍵結原子予以鍵結完成’使整個複晶矽 氧化膜層與摻雜磷之第1複晶砂層之間形成良好的氧化膜 /複晶矽界面，致使以陽極氧化法成長之複晶矽氧化膜品 質達到最佳化。 圖1(d)，快速退火處理完成後，於試片上再次利用低 壓化學氣相沉積法，沉積一層厚度3500埃摻雜磷之第2 複晶矽層50。 經濟部中央搮率局舅工消費合作社印製 圖1(e)，摻雜磷之第2複晶矽層50經黃光製程與蝕刻 製程，定義出閘極區域51。 圖1(f)，接著使用化學氣相沉積法成長厚度約6000埃 之二氧化矽保護層60。 圖1(g)，二氧化矽保護層經黃光製程與蝕刻製程開出 接觸孔(Contact hole)，並蒸鑛厚度約5000埃的鋁金屬後， 本紙倀尺度適用中國國冢榡準（CNS ) A4規格（210x297公釐） 經濟部中央標準局員工消費合作杜印製 6 95 3 7 at ______ B7 五、發明説明（斗） , 使用黃光製程與触亥ί!製程來定義鋁金屬電極7〇，完成複晶 矽-氧化膜-複晶矽電容器的製作。 圖2爲陽極氧化法之設備示意圖，包含了容器8〇，容 器80內裝有電解溶液81，白金(Pt)82部分浸在電解溶液 81中’及砂晶片/—氧化砂層/第1複晶砂層(1〇/20/30) 部分浸在電解溶液81中。當直流電源供應器83的陽極接 於第1複晶矽層30，陰極接於白金82並通入一雷壓後， 陽極端的第1複晶矽層3〇發生氧化反應形成複晶矽氧化 膜，陰極端則發生還原反應形成氫氣。 圖3爲圖1所述陽極複晶砂氧化膜 Polyoxide) ’與以傳統彳央速熱氧化法在複晶矽上成長二氧化 矽膜(RTO Polyoxide)做成之複晶矽-氧化膜_複晶矽電容器 之電流密度與電場關係比較圖。在此圖中，明顯地可看出 無論在正偏壓(+bias咸負偏壓(-bias)下，Anodic Polyoxide 之電容器具有較低的漏電流及較高的崩潰電場等特性。以 傳統快速熱氧化法在複晶矽上成長二氧化矽膜的詳細製程 條件如下： RTO Polyoxide製程條件：使用快速退火爐，於〇2氣 體中，850°C下，時間爲75秒，在複晶较上成長二氧化砍 膜，其RTO Polyoxide的厚度經由電容-霉壓沏f得70埃。 圖 4 爲 Anodic Polyoxide 與 RTO Polyoxide 在定電流 應力施加(Constant Current Stress)下之穩定性比較圖。在此 圖中，利用l〇_2A/cm2的定電流密度應力施加在試片上，量 測其電壓平移量(Voltage Shift) 〇無論在正偏壓(+bias烕負 -6" 本紙張尺度適用中國國家標準（CNS ) Α4規格（210 X 297公釐） ---------------.訂------^ (請先閲讀背面之注意事項再填寫本頁) >9537 A7 ----!Z_. 五、發明説明（了） ’、Five 'invention description (2J supply for non-volatile memory element manufacturing technology. ~ Invention description) The present invention discloses a polycrystalline silicon oxide film, which is characterized in that the polycrystalline silicon oxide film is formed by anodization. The present invention It is also revealed that the growth of the polycrystalline silicon oxide film by anodic oxidation method, which can be improved by rapid annealing optimization, can improve the quality of the polycrystalline silicon oxide film. It has been experimentally proven that the polycrystalline silicon oxide film formed by this method has a higher temperature than the traditional one Furnace or rapid thermal oxidation growth of the polycrystalline silicon oxide film has a flatter interface, better electrical characteristics and reliability. Therefore, the use of anodic oxidation method to grow the oxide film on the polycrystalline silicon, for strengthening non-volatile memory elements The ability to store data has been greatly improved. Detailed Description of the Invention The present invention provides an anodizing method for growing a high-quality, polycrystalline silicon oxide film at room temperature for use in non-volatile memory elements. The polycrystalline silicon oxide film is essentially a non-porous oxide film with no residual impurities and a flat surface. In order to test its electrical characteristics, Polycrystalline silicon oxide film grown by anodic oxidation method and rapid thermal oxidation of polycrystalline silicon oxide film to produce polysilicon-oxide film-polysilicon-polysilicon capacitors. The thicknesses are all 70 angstroms. Specific embodiments of the present invention will be described below with reference to FIGS. 1 (a) to 1 (g). -4- HI In I— HI 1 n ^ n 1 n ί Ϊ 3, Ί ( Please read the precautions on the back before filling this page) This paper size applies Chinese National Standard (CNS) Α4 specification (210X297 mm) 0 9 5 3 7 A7: __ · _B7 ____ _ V. Description of the invention (3) Figure 1 ( a) After the silicon wafer 10 is processed by the RCA standard rinsing process, firstly, a layer of 1000 angstroms of sand dioxide layer 20 is grown on the surface of the sand wafer 10 in a high-temperature furnace. Figure 1 (b), using low pressure chemical vapor deposition method, A layer of phosphorous-doped first polycrystalline silicon layer 30 with a thickness of 3500 angstroms is deposited. Figure 1 (c), after another RCA standard washing process, the silicon wafer is placed in an electrolytic solution (0.01% citric acid solution) ), At 23 ° C, the first polycrystalline silicon layer 30 doped with phosphorus is connected to the anode, and the voltage (35 volts) is applied for 3 minutes to make An oxidation reaction occurs on the surface of the first polycrystalline silicon layer of doped phosphorus to form a polycrystalline silicon oxide film 40. This polycrystalline silicon oxide film (about 70 angstroms thick) is then annealed at a temperature of 850 ° C in N2 gas and annealed In 30 seconds, the unbonded atoms at the oxide film / polycrystalline silicon interface are bonded to complete the formation of a good oxide film / multicrystalline silicon interface between the entire polycrystalline silicon oxide film layer and the first doped polycrystalline silicon sand layer. As a result, the quality of the polycrystalline silicon oxide film grown by the anodic oxidation method is optimized. Figure 1 (d), after the rapid annealing process is completed, a low-pressure chemical vapor deposition method is used to deposit a layer with a thickness of 3500 angstroms on the test piece. Phosphorous second polycrystalline silicon layer 50. Printed by the Central Government Bureau of the Ministry of Economic Affairs, Machining and Consumer Cooperatives Figure 1 (e). The second polycrystalline silicon layer 50 doped with phosphorous is defined by a yellow light process and an etching process to define the gate region 51. In FIG. 1 (f), a silicon dioxide protective layer 60 having a thickness of about 6000 angstroms is grown using a chemical vapor deposition method. Figure 1 (g). After the silicon dioxide protective layer is exposed to the contact hole through the yellow light process and the etching process, and the aluminum metal with a thickness of about 5000 angstroms is vaporized, the paper standard is applicable to the Chinese national standard ) A4 size (210x297 mm) Printed by the staff of the Central Bureau of Standards of the Ministry of Economic Affairs, printed 6 95 3 7 at ______ B7 V. Description of the invention (bucket), using the yellow light process and the contact process to define aluminum metal electrodes 7 〇 Complete the production of polycrystalline silicon-oxide film-multicrystalline silicon capacitors. Figure 2 is a schematic diagram of the equipment of the anodizing method, which includes a container 80, an electrolytic solution 81 contained in the container 80, platinum (Pt) 82 partially immersed in the electrolytic solution 81 ', and a sand wafer / -oxide sand layer / first polycrystal The sand layer (10/20/30) was partially immersed in the electrolytic solution 81. When the anode of the DC power supply 83 is connected to the first polycrystalline silicon layer 30 and the cathode is connected to the platinum 82 and a lightning pressure is applied, the first polycrystalline silicon layer 30 at the anode end undergoes an oxidation reaction to form a polycrystalline silicon oxide. The membrane and the cathode end undergo a reduction reaction to form hydrogen. FIG. 3 is a polycrystalline silicon-oxide film made of the anode polycrystalline sand oxide film described in FIG. 1 and a silicon dioxide film (RTO Polyoxide) grown on the polycrystalline silicon by a conventional rapid thermal oxidation method. A comparison chart of the relationship between the current density and the electric field of a crystalline silicon capacitor. In this figure, it can be clearly seen that Anodic Polyoxide capacitors have lower leakage currents and higher breakdown electric fields, regardless of positive bias (+ bias). The detailed process conditions for growing a silicon dioxide film on polycrystalline silicon by thermal oxidation are as follows: RTO Polyoxide process conditions: using a rapid annealing furnace in a 0 2 gas at 850 ° C for 75 seconds. The thickness of RTO Polyoxide grows to 70 angstroms through the capacitor-mold pressure when growing a film of dioxide. Figure 4 is a comparison chart of the stability of Anodic Polyoxide and RTO Polyoxide under Constant Current Stress. In this figure In the test, a constant current density stress of 10-2A / cm2 was applied to the test piece, and the voltage shift was measured (Voltage Shift). Regardless of the positive bias (+ bias 烕 negative-6), this paper size is applicable to Chinese national standards (CNS) Α4 specification (210 X 297 mm) ---------------. Order ------ ^ (Please read the notes on the back before filling this page) > 9537 A7 ----! Z_. V. Description of the Invention
偏壓(-bias)，Anodic Polyoxide的電壓平移量都較RTOBias (-bias), the voltage translation of Anodic Polyoxide is more than RTO
Poly oxide小很多，充分證明此Anodic Polyoxide具有較佳 的信賴性。 圖式之簡單說明 圖1(a)〜圖1(g)爲本發明實施例之一，來形成非揮發 性記憶、體元件複晶矽-氧化膜-複晶矽電容器構造之流程示 意圖。 圖2爲陽極氧化法之設備示意圖。 圖3爲以陽極氧化法在複晶矽上成長氧化膜(Anodic Polyoxide)並經RTP退火處理，與以快速熱氧化法在複晶 矽上成長氧化膜(RTO Polyoxide)做成之複晶矽-氧化膜-複 晶矽電容器之電流密度與電場關係比較圖。 圖 4 爲 Anodic Polyoxide 與 RTO Polyoxide 在定電流 應力施加下之穩定性比較圖。 1- 装-- {請先閲讀背面之注意事項再填寫本頁) *^τ 經濟部中央標準局—工消費合作杜印製 本紙張尺度適用中國國家標導（CNS )·Λ4規格（210Χ 297公釐）Poly oxide is much smaller, which fully proves that this Anodic Polyoxide has better reliability. Brief Description of the Drawings Figures 1 (a) to 1 (g) are one embodiment of the present invention, and the schematic diagram of the process of forming a non-volatile memory, body element, polycrystalline silicon-oxide film-multicrystalline silicon capacitor structure is shown. Figure 2 is a schematic diagram of the equipment of the anodizing method. Figure 3 is an anodic oxidation method to grow an oxide film (Anodic Polyoxide) on the polycrystalline silicon and RTP annealing treatment, and a rapid thermal oxidation method to grow the oxide film (RTO Polyoxide) on the polycrystalline silicon- Comparison diagram of the relationship between the current density and the electric field of an oxide film-polycrystalline silicon capacitor. Figure 4 is a comparison of the stability of Anodic Polyoxide and RTO Polyoxide under constant current stress. 1- Install-{Please read the notes on the back before filling this page) * ^ τ Central Standards Bureau of the Ministry of Economic Affairs-Industrial-Consumer Cooperation Du Printed This paper is sized for China National Standards (CNS) · Λ4 (210 × 297) Mm)