利用ECRCVD分析微晶矽與製作薄膜太陽電池

Analysis of microcrystalline silicon and fabrication of thin film solar cell by ECRCVD

黃志強(Chih Chiang Huang)

指導教授 ： 黃惠良

國立清華大學/電機資訊學院/電子工程研究所/碩士(2006年)

https://doi.org/10.6843/NTHU.2006.00224

摘要

在本篇論文中，我們探討於低溫下(250℃)，於電子迴旋式共振化學汽相沉積(ECRCVD)系統中，利用氫稀釋甲烷法，在二氧化矽和玻璃基板上成沉積硼與磷摻雜微晶矽薄膜。同時利用電腦模擬軟體來進行元件厚度最佳化的工作，最後依照實驗以及模擬的最佳參數，製作微晶矽薄膜太陽電池，並且量測元件的電流 – 電壓特性。

在實驗中，我們固定基板溫度(250℃)，微波能量(1150W)，以及製程壓力(20mTorr)，改變氫氣的流量，來觀察薄膜的特性。我們利用Raman光譜儀，FTIR光譜儀，X-ray 繞射儀，Nanospac 和 α-step 測厚儀，I-V特性量測，四點探針，以及掃描式電子顯微鏡(SEM)和展阻量測(SRP)等等，分別對薄膜的厚度變化，結晶性，晶粒大小，鍵結結構變化，光暗電導，摻雜濃度，電阻率等等特性來分析。同時在探討氫氣的稀釋比對薄膜結構的影響，引用了氫的蝕刻模型來解釋氫的誘發結晶機制，在成長過程中，氫離子傾向與不穩定鍵結的矽反應，並將此弱鍵結的矽原子帶走，留下穩定的矽鍵結，因此能在低溫下成長出微晶矽薄膜。在完成薄膜分析後，可以利用這些薄膜來製作PIN薄膜微晶矽太陽電池，並且在財團法人自強工業科學基金會，量測太陽電池的特性。

實驗結果顯示，我們使用氫稀釋甲烷法，在氫稀釋比92%時，有較高的結晶度(>90%)，與較大尺寸的結晶顆粒(>250A)，在氫稀釋比從40%增加到96%時，矽鍵結結構會從2000cm-1移位至2100cm-1，氫含量也隨著氫稀釋比增加而減少，
在摻雜方面，N-type濃度在1.24e17cm-3，P-type濃度在3.67e17cm-3。而在元件特性方面開路電壓為0.499V，短路電流為0.33mA，填充因子為20.62%。

關鍵字

微晶矽 ； 太陽電池

並列摘要

In this thesis, we do analysis of boron and phosphorus doped microcrystalline silicon and undoped microcrystalline silicon thin films deposited on glass and 4` wafer substrates by electron cyclotron resonance chemical vapor deposition (ECRCVD). Meanwhile, by using CAD(Computer Aided Design) tools, we optimized the device thickness structure. Finally, according to our best recipe, fabricate microcrystalline thin film solar cell, and I-V measurement are taken as the device characteristics.

In experiment, we fixed substrates temperature at 250℃, microwave at 1150W, pressure at 20mTorr, change flow rate of H2 observed the films characteristics. The film thickness, crystalline fraction, grain size, bonding configurations, dark and light conductivities, doped concentration, resistivity of μc-Si:H films were measured and analyzed by Raman spectroscopy, FTIR spectroscopy, X-ray diffraction (XRD),Nanospac andα-step depth profile, I-V measurement, 4-point probe, and SEM, SRP. The Etching model was introduced to explain the effect of hydrogen dilution ratio on the structure of uc-Si:H films. Hydrogen-etching reaction was explored as a major dynamics in determining the crystallization of silicon films. The preferential elimination of energetically unfavorable configurations by hydrogen etching attributes
to low-temperature-crystallized silicon films. In finish analysis of thin films, we can use best recipe fabricate PIN thin film solar cell, and measurement at Tze Chiang Foundation of Science and Technology.

The experiment results show that, hydrogen dilution ratio at 92% having high crystalline fraction(>90%), and large grain size(>250A), hydrogen dilution ratio between 40% to 96%, the bonding configurations from 2000cm-1 to 2100cm-1, and hydrogen content decreased when hydrogen dilution ratio increased. the doped concentration at N-type is about 1.24e17cm-3 , P-type is about 3.67e17cm-3 . in device measurement results, the Voc is about 0.4999V, Isc is about 0.33mA, Fill factor is about 20.62%.

並列關鍵字

microcrystalline silicon ； solar cell

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