Influence of gas mixture ratio on properties of SiNx:H films for crystalline silicon solar cells
- 주제(키워드) silicon nitride , passivation , silicon solar cells , gas mixture , optical property , field effect
- 발행기관 고려대학교 대학원
- 지도교수 김동환
- 발행년도 2012
- 학위수여년월 2012. 2
- 학위구분 석사
- 학과 일반대학원 신소재공학과
- 원문페이지 110 p
- 실제URI http://www.dcollection.net/handler/korea/000000034043
- 본문언어 영어
- 제출원본 000045697017
초록/요약
The Hydrogenated silicon nitride (SiNx:H) using plasma enhanced chemical vapor deposition is widely used in photovoltaic industry as an antireflection coating and passivation layer. In the high temperature firing process, the SiNx:H film should not change the properties for its use as high quality surface layer in crystalline silicon solar cells. Initially PECVD-SiNx:H film trends were investigated by varying the deposition parameters (temperature, electrode gap, RF power, gas flow rate etc.) to optimize the process parameter conditions. For optimized surface layer in crystalline silicon solar cells, by varying gas mixture ratios (SiH4+NH3+N2, SiH4+NH3, SiH4+N2), the hydrogenated silicon nitride films were analyzed for its optical, electrical, chemical and surface passivation properties. The SiNx:H film properties of refractive indices (2.0±0.03) and similar deposition rate (±150 Å/min) were fixed. The deposition was carried out at low temperature (370 ℃) in a direct plasma generator and matcher operating at 13.56 MHz and 1 KHz. The film deposited with the gas mixture of SiH4+NH3+N2 showed the best properties in before and after firing process conditions. The single crystalline silicon solar cells fabricated according to optimized gas mixture condition (SiH4+NH3+N2) on large area substrate of size 156 mm x 156 mm (Pseudo square) was found to have the conversion efficiency as high as 17.2 %. The reason for the high efficiency using SiH4+NH3+N2 is because of the good optical transmittance and passivation properties. Optimized hydrogenated silicon nitride surface layer and high efficiency crystalline silicon solar cells fabrication sequence has also been explained in this study.
more목차
Chapter 1. Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1
Chapter 2. Theoretical Background - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6
2.1 Solar Cells - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6
2.1.1 Operating principle of solar cells - - - - - - - - - - - - - - - - - - - - - - - - 6
2.1.2 Current-Voltage characteristics - - - - - - - - - - - - - - - - - - - - - - - - - 10
2.1.3 Solar cells parameters - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 13
2.1.4 Loss mechanism of solar cells - - - - - - - - - - - - - - - - - - - - - - - - - - - 15
2.2 Silicon Solar Cells - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 18
2.2.1 Screen printed solar cell - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 23
2.3 Recombination - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 26
2.3.1 Surface recombination - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 26
2.3.2 Bulk recombination process - - - - - - - - - - - - - - - - - - - - - - - - - - - - 27
2.4 Passivation for silicon solar cells with SiNx:H- - - - - - - - - - - - - - - - - - - - 30
2.4.1 Surface passivation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 32
2.4.2 Bulk passivation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 33
2.4.3 Physical Mechanisms for Recombination at the Si/SiNx:H interface - 34
Chapter 3. Hydrogenated SiNx:H film property trends according to the PECVD
Process parameters (investigating the effect of PECVD process parameters on SiNx:H properties) - - - - - - - - - - - - - - - - - - - - - - - - - -
42
3.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 42
3.2 Experiment - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 43
3.3 Results and discussion - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 48
3.4 Conclusions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 41
54
Chapter 4. A study on the gas mixture ratios on properties of SiNx:H film - - - - - 67
4.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 67
4.2 Experiment - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 67
4.3 Results and discussion - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 70
4.4 Conclusions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 90
References - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 91
