以濺鍍法製作矽異質接面太陽能電池之研究:矽薄膜特性對元件效率的影響

Research of High Efficiency Silicon Heterojunction Solar Cell Fabricated by Sputtering:Impact of Silicon Thin Film Properties on Device Performance

王宣文(Hsuan-Wen Wang)

指導教授 ： 李正中 ； 陳昇暉

國立中央大學/理學院/光電科學研究所/博士(2012年)

摘要

濺鍍為一種廣泛應用於薄膜成長，且具有許多優點的技術。然而對於矽薄膜的成長而言，濺鍍製程中的離子轟擊效應會使薄膜產生微孔洞，造成電性上的缺陷。因此濺鍍所製作的薄膜易形成矽氫多鍵結構與不易摻雜的特性。所以使用濺鍍法製作太陽能電池的難度較高，未能普及。
本研究使用磁控濺鍍來成長含氫矽薄膜並應用此方法製作矽異質接面太陽能電池。研究發現對基板施加正偏壓下，可有效使矽氫多鍵轉變為矽氫單鍵之穩定型態，且可藉由調變濺鍍功率與氣壓等參數來提升薄膜的摻雜效率。此外再以提升摻雜的P型矽薄膜成長於N型矽晶片表面來製作異質接面太陽能電池。於選擇適當的薄膜製程條件下，可在平面型(未表面粗糙化)的矽晶片獲得10%轉換效率之異質接面太陽能電池。

關鍵字

異質接面太陽能電池 ； 矽薄膜 ； 磁控濺鍍

並列摘要

Sputtering is a popular technique with many advantages for thin film deposition. However, as for the preparation of hydrogenated silicon thin film, ion bombardment accompanies during sputtering may generate microstructures (voids, columnar structures) within the film, which leads to unfavorable silicon dihydride bodings and electrical defects. Therefore, hydrogenated silicon films fabricated by sputtering are hard to be doped. Those inferior properties made sputtering become non-popular in the fabrication of silicon thin film cells.
In this research, we improved the qualities of hydrogenated silicon thin films and investigated electrical and optical properties with respect to deposition parameters. Our results indicated that applying positive bias voltage on the substrate provokes silicon monohydride formation, which is a rather stable bonding configuration as compared to silicon dihydride. Besides, the difficulties of doping can be reduced by refining fabrication parameters such as sputtering power and gas pressure. Futhermore, amorphous P-type / crystalline N-type silicon heterojunction solar cell using non-texture wafer surface has also been demonstrated. Proto-type solar cells with 1cm × 1cm area and 10% conversion efficiency were realized by choosing the appropriate sputtering parameters.

並列關鍵字

heterojuction solar cell ； silicon thin film ； magnetron sputtering

參考文獻

[1.2] W. Schockley and H. J. Queisser, “Detailed balance limit of efficiency of p-n junction solar cells”, J. Appl. Phys. 32 (1961) 510-519.

[2.1] J. Tauc, “Optical properties and electronic structure of amorphous Ge and Si”, Mat. Res. Bull. 3 (1967) 37-46.

[2.2] R. C. Chittick, J. H. Alexander and H. F. Sterling, “The preparation and properties of amorphous silicon”, J. Electrochem. Soc. 116 (1969) 77-81.

[2.3] W. E. Spear and P. G. LeComber,”Investigation of the localized state distribution in amorphous Si films”, J. Non-Cryst. Solids 8-10 (1972) 727-738.

[2.4] W. E. Spear and P. G. LeComber,”Subsitutional doping of amorphous silicon”, Solid State Commun. 17 (1975) 1193-1196.