578236 玖、發明說明： 【韻^明戶斤屬控^掏貝域^ 相關申請案的相互對照 [0005】’本案主張2002年六月28曰提出申請的美國 5專利暫時申請案序號第60/391,972,號以及2002年九月 15曰提出申請的英國專利申請案第〇122333.8號的優先 權。 發明背景 1 · 發明的袓關領域 10 [0010] 本發明係與形成氮化物薄膜的方法有關且特別 地，但是不是專門地，與氮化矽薄膜的形成有關。 t 3^0 前 3 2· 相關技藝術的說明 [0015]各種不同材質之薄膜的使用至今仍在增加，且在許 15多應用中提供不同材質的薄膜堆疊係變得更常見的。通常 此種的薄膜堆疊在加工步驟的一些階段中需要退火，而這 可能會因為來自比較低的層的排氣現象與因為在薄膜裡面 之應力的碎裂現象而造成氣泡產生。 [0020】 其之一個特別的例子發生在例如用於GaAs場 20效電晶體的製造之砷化鎵基材上的氮化矽沈積中，其中 GaAs基材的雜質植入作用需要一後續的高溫退火處理以 修復aa格的損害並’’活化”植入物。這個典型地是在7⑽。^ 或更高的溫度下（雖然低至65〇〇C的溫度已經有被使用） 的退火處理，容易造成來自砷化鎵基材的砷之向外擴散且 25因此需要一具有較好的障壁性和黏附性以及抗碎裂性的覆 蓋層，尤其在較高的溫度下。典型地係使用氮化矽。如果 覆蓋作用層只是用來犧牲的話，其係典型地為小於2〇〇nm 5 ^236 1厚度 <旦疋當它係將要具有一例如介電層的功能性特質 日守，已知其會具有400nm或更大的厚度之數個層次。 [0025】料的標準沈積加工方法會造成氣泡，且在比較 厚的薄膜時會碎裂。 5 【發明内容】 發明摘要 [0030}申請人已經研發一種用於形成較不易碎裂的氣 化石夕薄膜的方法，而至少在某些具體例中，該等方法也能 處理氣泡的問題。 10 [0G35】彳mi樣上，本發明係在於沈積—氮化石夕薄，膜 的方法，其包括將一含矽氣體導入腔室的電漿區域，分子 氮氣和充份的氫氣以分離氮，以允許矽和氮在鄰近的電漿 區域之表面上反應形成一氮化石夕。 [0040】 這與使用氨（NH3)做為氮來源的電漿化學蒸汽 15沈積加工相反。一般來說分子氮氣並不被視為氮來源，因 為氮氣的三價鍵結使其通常不穩定而難以分離。實際上由 於其在傳統的低溫（少於450°C)的電漿加工中，被認為是 如此不具活性的，因此其係在矽烷/氨加工方法中被廣泛地 用來作為惰性稀釋劑。 20 [0045]申请人已經發現的在氫存在下且特別是分子氫 氣存在下，該分子氮氣即使在一相對低能量和溫度的電漿 處理中都能被分離，而使得一氮化石夕薄膜可被形成。 [0050] 如下述中所證實的，從薄膜的應力與因此造成的 碎裂之觀點來看，這是相當有利的。 25 [0055] 較佳地，該含矽氣體係為矽烷且其已經被發現在 非常低的矽烷流速下，可以達成可接受的沈積率。舉例來 說’石夕烧流速可能少於10 seem並且實際上可以較佳地為 大約是2 seem 。 6 578236 【〇:】+人驚訝地，較佳地分子氮氣的流速也可以比氫 的肌速大，即，相較於氮氣含量，氮的存在量係顯然較少 的在特別的具體例中，氮的流速可以界於700和 9〇〇SCCm之間，而氫的流速可以界於500和800 seem之 5 間。 [〇〇65] 在電漿區域中的電漿可以是一高頻率（例如 13.56百萬赫茲）電漿，而供給至該電漿的電力可以低至例 如50和15〇w之間。 100701該方法可以更進一步包括使用一 n2電漿來清 ίο潔該表面。這個清潔步驟不能是太侵蝕性而顯著地改變該 表面的結構。如在下述中所證實的，使用此種處理可以除 去氣泡。 [00751 從另外的一個態樣中，本發明係在於一種形成氮 化物薄膜的方法，其包含將一要被氮化之元素來源、分子 15氮氣與充份的氫導入該腔室的電漿區域，以分離氮氣而允 許該兀素和氮產生反應而在一鄰近該電漿區域的表面上形 成一氮化物薄膜。 [0080】 較佳地該元素係為一例如過渡金屬之金屬。 [0085】 從又另一態樣中，本發明係在於具有較低的 20 Sl_H和N-H鍵結之氮化矽薄膜，特別是如ftir鍵結尖 峰區域为析（FTIR bonding peak area analysis)中所顯示 的。因此Si-H:Si-N的鍵結尖峰區域分析可能會<〇 〇2， 而N-H:Si-N鍵結尖峰區域分析可能會<〇 〇〇7。本發明也 包括一包含有依據上述的方法沈積的氮化矽薄膜，或包含 25有如上述所界定之薄膜的砷化鎵場效電晶體。 圖式的簡要說明 [0090】 雖然本發明已經在上述中界定，要了解的是其包 括在上述或下述中所描述任何各項特徵的發明組合。本發 7 578236 明可以用各種不同的態樣來施行，其現在將會以參照相斜 應的圖式的方式來加以例示說明： 第1圖係為沈積在一砷化鎵層上的經退火的矽層之顯 - 微圖， 5 第2圖係為相同加工方法但為較薄的薄膜之對應的影 像； 第3圖是第1圖的一對應的影像，但是其中砷化錁薄 膜係被預先清除的； 第4圖是第3圖的相等影像，只是其係為另一種沈積 10 力σ工方法； 第5圖係為在下述中的各種不同加工處理之薄膜的 FTIR光譜；且 第6圖是依據本發明的經退火之氮化矽薄膜的沈積顯 微圖。 15 【實施方式】 較佳具體例的詳細說明 100951基於所耠述的理由，申請人希望在砷化鎵上沈積 -定化學計量的氮化梦。化學計4的氮化㈣常係以 折射率2來代表。因此，申請人正在找尋具有此種折射率 2〇和良好的（例如在整個晶圓中）—致性之可接受的薄膜。 = 100】巾請人使用如下述表i所界定的標準氮化石夕覆 .盍加工方法來開始他們的實驗，而這產生一具有如表2中 所示的性質之薄膜。 表1-習知的高頻率加工方法（加工方法A) 矽烷 seem 氮 Seem 氨 Seem 壓力 mTor r 壓板 溫度 喷頭 溫度 射頻 能量 頻率 8 300 3500 700 850 300° C 300° C 100 W 一~----η 13.56 百萬赫兹 表2-加工方法序A的薄膜之性質（15()公釐的基材） 厚度 一致 性 (%) 折射 率 濕式蝕 刻速率 10:1 BHF 在700°退 火作用之 後的濕式 蝕刻速率 沈積 應力 達因/cm2 在700°退火 作用之後的 沈積應力 a達因/cm2 應力 變化 達因 /cm2 <2% 1.999 34奈米/ 分鐘 3奈米/分 鐘 -7E8 壓縮 +8E9 張力 8.7E9 578236 [〇1〇5] 第1和2圖顯示在700°C退火作用之後厚度 5分別為400nm和10〇nm的這些薄膜之顯微照片。如其所 示，兩個薄膜都可看見嚴重的起泡現象，而該厚的薄膜顯 示了碎裂現象。 [0110】 申請人假設該起泡現象係因為在氮化矽的退‘ 火覆蓋作用的沈積之前，推測會形成一天然的氧化鎵，而 1〇引起沈積至砷化鎵的表面上的薄膜之較差的黏附性所導致 的。他們因此使用一高頻率氫電漿來預先清理該表面並重 新進订該實驗。結果顯示在第3圖中，而要注意的是雖然 碎裂現象仍然存在，該起泡現象已經被完全移除。 [0115】 已知這種類型的電漿處理可以改變表面抵抗力 15且甚至改變結晶結構。因此將該預先清理作用最小化到 避免乳泡的必需程度是重要的。所需要的清潔程度將會因 環境而改變並且係可自實驗上得知。 [0120】、薄膜碎裂現象通常與呈現張應力的薄膜有關。雖 然習知的加工方法A在表！和2中顯示沈積的壓縮應 9 578236 力，該薄膜在700。(：的退火作用之後會變成高張力的。進 一步的貫驗因此以另一種習知的加工方法（加工方法則 進行，其已知道會產生高壓縮應力的薄膜。該加工方法和 所得到的薄膜特性係顯示在下述的表3和4裡面。 表3-習知技藝的低頻率加工方法（加工方法b) 矽烷 seem 氮 Seem 「氨 Seem 壓力 mTorr 壓板溫 度 噴頭溫 度 射頻能 量 頻率 300 3500 700 850 300°C 300°C 1 500 W 380仟 赫 表4-加工方法b的薄膜之性質（15〇公釐的基材） 厚度 一致 性 (%) 折射 率 濕式蝕 刻速率 10:1 BHF 在700。退 火作用之 後的濕式 蝕刻速率 沈積應 力 達因 /cm2 在700°退火 作用之後的 沈積應力 達因/cm2 應力變 化 達因 /cm2 <2% 2.001 11奈米/ 分鐘 2.8奈米/ 分鐘 -5E9 壓縮 - +2.2E9 張力 7.2E9578236 发明, Description of the invention: [Yun ^ Minghu Jin belongs to the control ^ shellfish domain ^ Mutual comparison of related applications [0005] 'This case claims that the United States 5 patent provisional application filed on June 28, 2002 No. 60 / Priority No. 391,972, and British Patent Application No. 0122333.8, filed on September 15, 2002. BACKGROUND OF THE INVENTION 1. Field of Invention 10 [0010] The present invention relates to a method for forming a nitride film and particularly, but not exclusively, to the formation of a silicon nitride film. t 3 ^ 0 before 3 2 · Description of related arts [0015] The use of films of different materials is still increasing, and it is more common to provide film stacking systems of different materials in more than 15 applications. Usually such thin film stacks need to be annealed during some stages of the processing steps, and this may result in air bubbles due to outgassing from lower layers and chipping due to stress in the film. [0020] A special example of this occurs in, for example, silicon nitride deposition on a gallium arsenide substrate used in the manufacture of GaAs field effect transistors, where the implantation of impurities by the GaAs substrate requires a subsequent high temperature Annealing to repair damage to the aa grid and "activate" the implant. This is typically annealed at 7 ° C. Or higher (although temperatures as low as 6500C have been used), It is easy to cause the outward diffusion of arsenic from the gallium arsenide substrate and therefore requires a cover layer with better barrier properties, adhesion and chipping resistance, especially at higher temperatures. Nitrogen is typically used If the cover layer is only used for sacrifice, it is typically less than 2000 nm 5 ^ 236 1 thickness < once it is about to have a functional property such as a dielectric layer. It is known that it will have several layers with a thickness of 400 nm or more. [0025] The standard deposition processing method of the material will cause bubbles, and will crack when the film is relatively thick. 5 [Abstract] Summary of the Invention [0030] Application People have developed a Methods of less-fragile gasified stone thin films, and at least in some specific examples, these methods can also deal with the problem of bubbles. 10 [0G35] On the sample, the present invention is based on deposition-nitrided thin films A membrane method comprising introducing a silicon-containing gas into a plasma region of a chamber, molecular nitrogen and sufficient hydrogen to separate nitrogen, and allowing silicon and nitrogen to react on the surface of an adjacent plasma region to form a nitride [0040] This is the opposite of the plasma chemical vapor deposition process using ammonia (NH3) as the nitrogen source. Generally molecular nitrogen is not considered as a nitrogen source because the trivalent bonding of nitrogen makes it generally not It is stable and difficult to separate. In fact, it is widely used as a silane / ammonia processing method because it is considered to be so inactive in traditional low-temperature (less than 450 ° C) plasma processing. Inert diluent. [0045] The applicant has discovered that in the presence of hydrogen and especially molecular hydrogen, the molecular nitrogen can be separated even in a plasma treatment of relatively low energy and temperature, so that a nitrogen fossil Even thin films can be formed. [0050] As demonstrated below, this is quite advantageous from the viewpoint of the film's stress and the resulting chipping. 25 [0055] Preferably, the silicon-containing gas system Is a silane and it has been found that an acceptable deposition rate can be achieved at very low silane flow rates. For example, the 'stone sintering flow rate may be less than 10 seem and may actually be better about 2 seem. 6 578236 [〇:] + Surprisingly, preferably, the flow rate of molecular nitrogen can also be greater than the muscle velocity of hydrogen, that is, compared to the nitrogen content, the amount of nitrogen present is obviously smaller. In a specific example, The flow rate of nitrogen can be between 700 and 900 SCCm, and the flow rate of hydrogen can be between 5 and 500 seem. [0060] The plasma in the plasma region may be a high-frequency (e.g., 13.56 megahertz) plasma, and the power supplied to the plasma may be as low as, for example, between 50 and 150 watts. 100701 The method can further include cleaning the surface using an n2 plasma. This cleaning step must not be too aggressive to significantly alter the structure of the surface. As demonstrated in the following, air bubbles can be removed using this treatment. [00751 In another aspect, the present invention resides in a method for forming a nitride film, which includes introducing a source of an element to be nitrided, molecular nitrogen, and sufficient hydrogen into a plasma region of the chamber. In order to separate the nitrogen and allow the element to react with the nitrogen, a nitride film is formed on a surface adjacent to the plasma region. [0080] Preferably, the element is a metal such as a transition metal. [0085] In yet another aspect, the present invention resides in a silicon nitride film with a lower 20 Sl_H and NH bond, especially as described in FTIR bonding peak area analysis. to show. Therefore, the analysis of the bonding peak region of Si-H: Si-N may be <0.002, and the analysis of the bonding peak region of N-H: Si-N bond may be <0.07. The present invention also includes a gallium arsenide field-effect transistor including a silicon nitride film deposited according to the method described above, or 25 gallium arsenide field-effect transistor including a film as defined above. BRIEF DESCRIPTION OF THE DRAWINGS [0090] Although the invention has been defined in the foregoing, it is to be understood that it includes an inventive combination of any of the features described above or below. The invention 7 578236 can be implemented in a variety of different forms, which will now be illustrated by referring to the corresponding diagram: Figure 1 is annealed deposited on a gallium arsenide layer The visible-micrograph of the silicon layer, 5 Figure 2 is a corresponding image of the same processing method but a thin film; Figure 3 is a corresponding image of Figure 1, but the samarium arsenide film is Cleared beforehand; Figure 4 is the equivalent image of Figure 3, but it is another method of deposition 10 force sigma method; Figure 5 is the FTIR spectrum of the thin film of various processing in the following; and Figure 6 FIG. Is a deposition micrograph of an annealed silicon nitride film according to the present invention. [Embodiment] Detailed description of a preferred specific example 100951 For the reasons stated, the applicant wishes to deposit a stoichiometric nitriding dream on gallium arsenide. The hafnium nitride of the chemical gauge 4 is usually represented by the refractive index 2. Therefore, applicants are looking for an acceptable film with such a refractive index of 20 and good (for example, throughout the wafer) consistency. = 100] To invite people to start their experiments using a standard nitrite coating method as defined in Table i below, this resulted in a film with properties as shown in Table 2. Table 1-Known high-frequency processing methods (Processing Method A) Silane see Nitrogen Seem Ammonia Seem Pressure mTor r Pressure plate temperature Nozzle temperature RF energy frequency 8 300 3500 700 850 300 ° C 300 ° C 100 W One ~ --- -η 13.56 megahertz Table 2-Processing method Sequence A's film properties (15 () mm substrate) Thickness consistency (%) Refractive index wet etching rate 10: 1 BHF after 700 ° annealing Wet etch rate Deposition stress dyne / cm2 Deposition stress after 700 ° annealing a dyne / cm2 Stress change dyne / cm2 < 2% 1.999 34 nm / min 3 nm / min-7E8 Compression + 8E9 Tension 8.7E9 578236 [00105] Figures 1 and 2 show photomicrographs of these films with thicknesses of 400 nm and 100 nm, respectively, after annealing at 700 ° C. As shown, severe blistering was seen in both films, while the thick film showed chipping. [0110] The applicant assumes that the blistering phenomenon is because a natural gallium oxide is speculatively formed before the deposition of the silicon nitride's flame-retarding effect, and 10 causes a thin film deposited on the surface of the gallium arsenide. Caused by poor adhesion. They therefore used a high-frequency hydrogen plasma to pre-clean the surface and reorder the experiment. The results are shown in Figure 3, and it should be noted that although the chipping phenomenon still exists, the blistering phenomenon has been completely removed. [0115] It is known that this type of plasma treatment can change the surface resistance 15 and even the crystal structure. It is therefore important to minimize this pre-cleansing effect to the extent necessary to avoid milk frothing. The degree of cleaning required will vary with the environment and can be determined experimentally. [0120] The film fragmentation phenomenon is usually related to a film exhibiting tensile stress. Although the conventional processing method A is on the table! And 2 shows that the compression of the deposit should be 9 578 236 force, the film is at 700. (: After annealing, it will become high tension. Further inspection is therefore performed by another conventional processing method (the processing method is performed, which is known to produce a film with high compressive stress. This processing method and the resulting film The characteristics are shown in the following Tables 3 and 4. Table 3-Low Frequency Processing Method (Processing Method b) of Silane Seem Nitrogen Seem "Ammonia Seem Pressure mTorr Pressure Plate Temperature Nozzle Temperature RF Energy Frequency 300 3500 700 850 300 ° C 300 ° C 1 500 W 380 Hz Table 4- Properties of the film of processing method b (substrate of 15 mm) Thickness consistency (%) Refractive index wet etching rate 10: 1 BHF at 700. Annealing Subsequent wet etch rate deposition stress dyne / cm2 Deposition stress dyne / cm2 after 700 ° annealing Stress change dyne / cm2 < 2% 2.001 11 nm / min 2.8 nm / min-5E9 Compression- + 2.2E9 Tension 7.2E9
[0125】 如所示雖然該沈積應力係顯著地比加工方法A 更加緊縮，在退火作用下，該應力的改變係為與加工方法A 1〇中所發生的類似之程度大小，且該經退火的薄膜係為一張 力薄膜。因此，在意料之中地，碎裂現象再次顯現且可見 於第4圖中。 [0130] 此種顯者程度的應力變化使得申請人考慮其是 否是為薄膜鍵結狀態的改變及/或在退火期間發生之排氣 15現象的結果。如第5圖所示，該加工方法之前與之後的 FTIR分析，顯示於退火過程之後在氫鍵鍵結狀態中的顯著 改變。 [0135] 從加工方法Α和Β的FTIR曲線圖中，申請 人推測在N-H和Si-H鍵結的減少會減低應力，且和他們 10 578236 因此尋求一種會達成此目的之加工方法。 [0140] 更進一步的說，申請人驚訝地了解在決定該薄膜 是否碎裂中，重要的不是其之整體的張力程度，而是在退 火過程期間應力的改變程度。他們進一步假設此種在應力 5 上係與在退火期間的氫損失程度有關。他們因此尋求了一 種不同的方式來形成氮化矽（也就是除了使用可以在氨中 得到的原子氮之外的方式），且發現了只要該存在有分子氫 氣以使得分子氮氣能夠分離並反應的話，使用矽烷和分子 氮氣來進行適當的反應是可能的。該較佳的實驗加工方法 10 係如下述的表5所示而所得到的薄膜係如表6中所例示 說明的。第6圖顯示所得到顯微影像，而可以發現其並沒 有碎裂解或起泡的現象。可以看見的小黑暗區域是被加入 以允許光學顯微鏡對焦的表面粒子。先前的碎裂現象係可 以幫助對焦的。可以了解H2的預先清除現象已經發生。[0125] As shown, although the deposition stress is significantly tighter than the processing method A, the change in the stress under annealing is similar to that occurring in the processing method A 10, and the annealed The thin film is a force film. Therefore, as expected, chipping appears again and can be seen in Figure 4. [0130] This apparent change in stress has caused the applicant to consider whether it is the result of a change in the bonding state of the film and / or the phenomenon of outgassing that occurs during annealing. As shown in Figure 5, the FTIR analysis before and after this processing method shows a significant change in the hydrogen bonding state after the annealing process. [0135] From the FTIR graphs of the processing methods A and B, the applicant speculated that the reduction of the N-H and Si-H bonds would reduce the stress, and therefore they sought a processing method that would achieve this goal. [0140] Furthermore, the applicant was surprised to understand that in determining whether the film is broken, it is not the degree of overall tension that matters, but the degree of change in stress during the annealing process. They further hypothesized that this stress 5 was related to the degree of hydrogen loss during annealing. They therefore sought a different way to form silicon nitride (that is, in addition to using atomic nitrogen available in ammonia), and discovered that as long as molecular hydrogen was present to allow molecular nitrogen to separate and react It is possible to use silane and molecular nitrogen for proper reactions. The preferred experimental processing method 10 is shown in Table 5 below, and the obtained film is shown in Table 6 as an example. Figure 6 shows the microscopic image obtained, but it was found that there was no fragmentation or blistering. Visible small dark areas are surface particles added to allow the light microscope to focus. Previous fragmentation can help focus. It can be understood that the pre-clearing phenomenon of H2 has occurred.
15 表5-本發明的加工方法C 矽烷 seem 氮 Seem 氨 Seem 壓力 mTorr 壓板溫 度 噴頭 溫度 射頻 能量 頻率 2 800 600 700 300°C 300°C 55 W 13.56百萬赫 茲 表6-加工方法C之薄膜的性質（150公釐的基材） 厚度 一致 性 (%) 折射 率 濕式蝕 刻速率 10:1 BHF 在700°退 火作用之 後的濕式 #刻速率 沈積 應力 達因 /cm2 在700°退火 作用之後的 沈積應力 達因/cm2 應力變化 達因/cm2 <2% 2.012 8奈米/ 分鐘 10.6奈米 /分鐘 +1E9 張力 +3E9張力 2E9 [0145] 表6顯示在退火期間應力的改變係顯著地減少 11 578236 (舉例來說，少於5E9 ’且如所示甚至少於3E9)，並確認了 即使該沈積薄膜係為拉張的，碎裂現象也已經被避免。該 加工方法的其他有趣特性是其溫度是低的（也就是在 450°C之下）、該矽烷流速係極低，且氮對氫的比例較在氨 5 中者係顯著地較低的。 [0150】 因此即使加工方法C係在加工方法A —半的 能量程度與〇·67%的矽烷流速下進行，其之沈積速率係在 習知的加工方法A之約60%的1〇_ 15奈米/分鐘。這可 能因而使該分子氫氣也促進石夕烧的分解。 10 [0155]下述的表7顯未薄膜收縮測量的結果。 表7-薄膜收縮資料 在退火作用之 前的厚度 在700°C退火作 用之後的厚度 收縮率％ 方法A 385.3 nm 370.8 nm 3.8 加工方法B 440.1 nm 426.9 nm 3.0 Jjvjl方法c 499.0 nm --------- 493.6 nm 1.1 [0160]如所示加工方法C提供一在植、入退火作用之 後具有顯著較少的收縮率（舉例來說，少於2% ,且如所 15不，甚至少於1.2%)的薄膜，其說明了在高溫處理期間該 薄膜之較佳的穩定性。 [0165】也要注意的是，從上述的表中加工方法a與b 的薄膜具有-在退火處理之後戲劇性地下降的濕式钱刻速 率。這通常代表了緻密化，其係與氫的損失且更常與薄 2〇膜，構的改變-致。如果不是因為碎裂現象這可能被視 為疋所欲的相較之下，在加工方法c的濕式姓刻速率中 的小幅變化’說明了該薄膜在退火期間僅有小幅的結構變 化0 [咖】因此藉由使用例如分子氫氣的氫來使用分子氣 12 578236 氣形成氮化物，已經能夠製造熱穩定性的薄膜。此外，使 用預先清潔的步驟，允許申請人移除起泡現象。 [0175】 下面表8和9提供在薄膜裡的鍵結之更詳細 的照片。其將會看見在加工方法C的薄膜中Si-N化學鍵 5 係被大幅地被增加，而Si-H和N-H化學鍵係被顯著地減 少。再者，加工方法C的退火前與後的數字比起加工方法 A和B的相對.應數值係較沒有改變的。這說明了熱穩定 性的改善。 表8-退火前與後FT1R之鍵結尖峰區域15 Table 5-Processing method C of the present invention Silane see Nitrogen Seem Ammonia Seem Pressure mTorr Pressure plate temperature Nozzle temperature Radio frequency energy frequency 2 800 600 700 300 ° C 300 ° C 55 W 13.56 MHz Table 6-Processing method C of film Properties (150 mm substrate) Thickness uniformity (%) Refractive index wet etching rate 10: 1 BHF Wet #etch rate after 700 ° Annealing Deposition stress dyne / cm2 After 700 ° Annealing Sedimentary stress dyne / cm2 Stress change dyne / cm2 < 2% 2.012 8 nm / min 10.6 nm / min + 1E9 tension + 3E9 tension 2E9 [0145] Table 6 shows that the change in stress during annealing is significantly reduced 11 578236 (for example, less than 5E9 'and even less than 3E9 as shown), and confirmed that even if the deposited film is stretched, chipping has been avoided. Other interesting characteristics of this processing method are that its temperature is low (ie, below 450 ° C), the silane flow rate is extremely low, and the ratio of nitrogen to hydrogen is significantly lower than that in ammonia 5. [0150] Therefore, even if the processing method C is performed at the energy level of the processing method A—half and the silane flow rate of 0.67%, the deposition rate is about 10% to about 15% of the conventional processing method A. Nanometers / minute. This may thus cause the molecular hydrogen to also promote the decomposition of Shi Xiyao. [0155] Table 7 below shows the results of the film shrinkage measurement. Table 7-Thin film shrinkage data. Thickness before annealing at 700 ° C. Thickness shrinkage after annealing. Method A 385.3 nm 370.8 nm 3.8 Processing method B 440.1 nm 426.9 nm 3.0 Jjvjl method c 499.0 nm ------ --- 493.6 nm 1.1 [0160] As shown, processing method C provides a significantly less shrinkage after implantation and annealing (for example, less than 2%, and as described above, not even less than 15%). 1.2%) film, which illustrates the better stability of the film during high temperature processing. [0165] It should also be noted that the films of processing methods a and b from the above table have a wet money engraving rate that dramatically decreases after the annealing process. This usually represents densification, which is related to the loss of hydrogen and more often to the thin 20 film, the change in texture. If it is not for the cracking phenomenon, this may be regarded as the comparison. A small change in the wet-type engraving rate of processing method c 'indicates that the film has only a small structural change during annealing. 0 [ [Ca] Therefore, by using molecular hydrogen such as molecular hydrogen to form nitride using molecular gas 12 578236 gas, it has been possible to produce a thermally stable thin film. In addition, the use of a pre-cleaning procedure allows the applicant to remove blistering. [0175] Tables 8 and 9 below provide more detailed photographs of the bonds in the film. It will be seen that the Si-N chemical bond 5 system is greatly increased and the Si-H and N-H chemical bond systems are significantly decreased in the thin film of the processing method C. Furthermore, the numbers before and after annealing for processing method C are relatively unchanged compared to the corresponding values for processing methods A and B. This illustrates the improvement in thermal stability. Table 8-Bonding spike areas of FT1R before and after annealing
Si-N Si-H N-H 以加工方法B沈積 71.420 4.131 0.687 以加工方法B退火之後 73.193 3.713 0.337 以加工方法A沈積 64.121 4.640 0.933 以加工方法A退火之後 73.193 3.713 0.337 以加工方法C沈積 102.621 1.222 0.541 以加工方法C退火之後 107.257 1.562 0.697 10 表9-退火前與後FUR之鍵結尖峰區域比例Si-N Si-H NH deposited by processing method B 71.420 4.131 0.687 deposited by processing method B 73.193 3.713 0.337 deposited by processing method A 64.121 4.640 0.933 deposited by processing method A 73.193 3.713 0.337 deposited by processing method 102.621 1.222 0.541 by Processing method C after annealing 107.257 1.562 0.697 10 Table 9- Proportion of peak area of FUR bond before and after annealing
Si-H:Si-N N-H:Si-N N-H:Si-H 以加工方法B沈積 0.0724 0.0146 0.2018 以加工方法B退火之後 0.0468 0.0034 0.0734 以加工方法A沈積 0.0578 0.0097 0.1663 以加工方法A退火之後 0.0507 0.0046 0.0908 以加工方法C沈積 0.0119 0.0053 0.4427 以加工方法C退火之後 0.0146 0.0065 0.4462 【圖式簡單說明】 第1圖係為沈積在一砷化鎵層上的經退火的矽層之顯 微圖； 第2圖係為相同加工方法但為較薄的薄膜之對應的影 15 像； 第3圖是第1圖的一對應的影像，但是其中砷化鎵薄 膜係被預先清除的； 第4圖是第3圖的相等影像，只是其係為另一種沈積 13 578236 加工方法； 第5圖係為在下述中的各種不同加工處理之薄膜的 FTIR光譜；且 第6圖是依據本發明的經退火之氮化矽薄膜的沈 5 積顯微圖。 【圖式之主要元件代表符號表】 無Si-H: Si-N NH: Si-N NH: Si-H Deposited by machining method B 0.0724 0.0146 0.2018 After annealing by machining method B 0.0468 0.0034 0.0734 Deposited by machining method A 0.0578 0.0097 0.1663 After annealing by machining method A 0.0507 0.0046 0.0908 0.0119 0.0053 0.4427 deposited by processing method C 0.0146 0.0065 0.4462 after processed method C [Simplified illustration] Figure 1 is a micrograph of an annealed silicon layer deposited on a gallium arsenide layer; Section 2 The picture shows the corresponding 15 images of the same processing method but a thin film; Figure 3 is a corresponding image of Figure 1, but the GaAs film has been removed in advance; Figure 4 is Figure 3 The equivalent image of the figure, but it is another deposition 13 578236 processing method; Figure 5 is the FTIR spectrum of the various processed films in the following; and Figure 6 is annealed nitridation according to the present invention Submerged micrograph of a silicon film. [Representative symbol table for main elements of the diagram] None
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