研究生: |
廖苡良 Yi-Liang Liao |
---|---|
論文名稱: |
大面積射頻電漿輔助化學氣相沉積系統製備氫化非晶矽膜作為矽晶鈍化層之研究 Surface passivation of c-Si wafers using a-Si:H layers prepared in large-area radio frequency plasma enhanced chemical vapor deposition system |
指導教授: |
洪儒生
Lu-Sheng Hong |
口試委員: |
陳良益
Liang-Yih Chen 周賢鎧 Shyan-kay Jou |
學位類別: |
碩士 Master |
系所名稱: |
工程學院 - 化學工程系 Department of Chemical Engineering |
論文出版年: | 2017 |
畢業學年度: | 105 |
語文別: | 中文 |
論文頁數: | 85 |
中文關鍵詞: | 射頻電漿化學氣相沉積 、氫化非晶矽 、有效少數載子生命期 、暗示開路電壓 、退火 |
外文關鍵詞: | Large-area RF-PECVD, a-Si:H, Minority carrier lifetime, Implied Voc, Annealing |
相關次數: | 點閱:597 下載:7 |
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本研究係在以較大面積(20×20 cm2)之射頻電漿輔助化學氣相沉積系統中,通入矽甲烷原料以不同製程條件於單晶矽表面沉積氫化非晶矽形成異質接合結構。研究重點在探究在此一沉積系統中氫化晶矽的鍍膜性質,期待找出對於單晶矽的表面鈍化效果較佳的長膜條件。
實驗結果顯示,在放電間距3 cm、電漿功率密度在1.59 mW/cm2時,有相對較小約1奈米的長膜表面粗糙度,其微結構參數為0.165。以此條件製作30奈米氫化非晶矽鈍化矽晶雙面後,於退火前晶片的載子生命期為1170 µs。另外調整原料進氣氫稀釋比為3的成長條件下,由RHEED繞射圖譜發現長膜已進入非晶與磊晶轉移區域,再經退火處理後,獲得晶片有效載子生命期為1630 µs、暗示開路電壓為718 mV。此時發現微結構參數大幅由0.15下降至0.03,顯示在低電漿功率密度的非晶矽長膜經退火處理後仍能展現良好的矽晶表面鈍化能力。
Hydrogenated amorphous Si (a-Si:H) thin films were deposited on single crystal Si (c-Si) wafers to form a-Si:H/c-Si heterojuction structure in large-area(20×20 cm2) radio-frequency plasma-enhanced chemical vapor deposition (large-area RF-PECVD) system. Emphasis was placed upon exploring the characteristics of a-Si:H film prepared in large-area RF-PECVD system and finding the optimized condition to obtain the high quality film which has less defect and dense structure. We expect to promote minority carrier lifetime of c-Si with these high quality films.
The result of experiment, when the discharge distance is 3 cm in large-area RF-PECVD system, it was found that film has a roughness layer thickness of 1.01 nm and a microstructure parameter of 0.165 at a minimum 1.59 mW / cm2 of plasma power density. When we deposited 30 nm a-Si:H on double side to passivate the polished silicon wafer, the as-deposited sample showes a minority carrier lifetime of 1170 µs. Therefore, we got more compact films at very low power density in large-area PECVD system.
In addition, when the hydrogen dilution ratio is 3, we observed that the amorphous/epitaxy transition by employing RHEED technique. The a-Si:H/c-Si heterojuction prepared under this condition showes a very high minority carrier lifetime of 1430 µs even for the as-deposited state. A further heat treatment promoted minority carrier lifetime only a little bit to 1630 µs, corresponding an implied Voc of 718 mV. The microstruture parameter down from 0.15 to 0.034, it shows that produce less microvoid after annealing, and have the best passivation performance.
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