矽薄膜之特性分析與異質結構薄膜太陽能電池之製作

Analysis of silicon thin film and fabrication of heterostructure thin film solar cell

吳立國(Li-Guo Wu)

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)

摘要

本篇論文主要是使用ECR-CVD系統以氫稀釋法來成長矽薄膜，並利用拉曼光譜儀、傅立葉轉換光譜儀、X光繞射儀、α-STEP測厚儀及I-V量測等儀器分別對薄膜的結晶性、氫鍵結結構變化、晶向及結晶顆粒大小、薄膜厚度、光暗電導等特性進行分析。在實驗過程中我們固定溫度為250度、壓力為20X10-3托、上中下磁場電流為170/170/30安培、微波功率為1150瓦特，改變氫稀釋比例為40%到98%進行分析。此外，我們也在矽薄膜中摻雜B2H6及PH3氣體形成P型及N型矽薄膜並對其電阻率進行比較。實驗結果顯示當氫稀釋比在92%時，我們可以的到較大的結晶顆粒約251 Ǻ及較高的結晶度約90%。
我們也利用模擬軟體AFORE-HET模擬最佳化的厚度，並利用模擬結果研製出矽薄膜太陽能電池，我們主要以P摻雜的非晶矽薄膜當 window layer，而I層及N層為則微晶矽薄膜。並由電流電壓特性得知其填充因子為21.35%、開路電壓為0.4V、短路電流為0.112mA/cm2。此元件的特性，還需要藉由改善各層材料性質來提升。

關鍵字

太陽能電池 ； 矽薄膜 ； 電子迴旋共症

並列摘要

Research work, we grew the silicon thin films with different hydrogen dilution ratio by electron cyclotron resonance chemical vapor deposition (ECR-CVD). The crystalline fraction, bonding configurations, crystalline orientation and grain size, film thickness, dark and light conductivities of the silicon thin films were measured and analyzed by the Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), α-STEP and I-V measurement respectively. In the experiment, we fixed the substrate temperature at 250oC, the process pressure at 20mtorr, the microwave power at 1150W, the Top/ Middle/ Bottom magnetic current at 170/170/30A and varied the hydrogen dilution ratio from 40% to 98%. Beside, we also doped the films using phosphine (PH3) and diborance(B2H6) to form the n-type and p-type silicon thin film. The four point probe was used to analyze the resistivity. From the experimental results, we find the fact that the maximum grain size was found to be about 251Ǻ and the maximum crystalline fraction was about 91% when the hydrogen dilution ratio was 92%.
AFORE-HET was used to simulate the optimum thickness of the device structure and followd the simulated result to fabricate the silicon thin film solar cell. The P-type amorphous silicon was used as a window layer and microcrystalline silicon as I and N layer. From I-V characteristics of the device, the open circuit voltage obtained is 0.112mA/cm2, the short circuit current is 0.4V and the fill factor is 21.35%. The device characteristics can be improved by improving the quality of the material.

並列關鍵字

solar cell ； silicon thin film ； ECR

參考文獻

Chapter 1

[2] Ruud E.I. Schropp, Miro Zeman, “Amorphous and microcrystalline silicon solar cell”, Kluwer Academic Publishers

[3] S. Veprek and F. A. Sarott, Phys. Rev. B36, 3344 (1987))

[5] Jerzy Kanicki, “Amorphous and Microcrystalline Semiconductor Devices VolumeІІ”, Artech House

[1] Ruud E.I. Schropp, Miro Zeman, “Amorphous and microcrystalline silicon solar cell”, Kluwer Academic Publishers