在此研究中，我們利用電子迴旋共振化學氣相沉積法（Electron Cyclotron Rasenance Chemical Vapor Deposition, ECR-CVD）來成長碳化矽薄膜並應用於矽晶異質接面太陽能電池( Heterojunction with Intrinsic Thin layer, HIT )。由於接面處會有許多懸浮鍵而會導致少數載子復合，日本三洋(Sanyo)公司已發表在單晶矽基板和射極層間加入氫化非晶矽薄膜並應用於本質層( i layer )，將可提高接面間的表面鈍化( passivation )而減少載子復合的發生，根據日本三洋公司研究其電池轉換效率已可達23 %。此篇所研究的非晶碳化矽薄膜，和氫化非晶矽薄膜在應用於矽晶異質接面太陽能電池的本質層上相較之下，有較好的溫度穩定性，其光吸收係數也較低使得光穿透率較高，並且也能擁有鈍化效果的特性，可以提升電池的短路電流Jsc ，並且在ECR-CVD製程中能讓實驗的薄膜鍍率減少且可增加調配範圍，可以讓電池的效率可依實驗參數調配再做提升。 我們先研究薄膜在改變氫氣稀釋混氣比、微波能量、工作壓力、 磁場及甲烷與矽甲烷的稀釋混合比時，晶相的轉變和其光性及電性，來得到較好成膜品質的條件，並探討本質層厚度、退火溫度對鈍化效果的影響，最後應用於具鈍化效果的異質接面太陽能電池中的本質層，並得到最佳優化的HIT太陽能電池。我們利用光放射光譜儀（Optical Emission Spectroscopy, OES）做電漿解離分析，之後可藉由橢圓儀量測光性如折射率並推算出光吸收係數小於氫化非晶矽薄膜且在波段為400 nm為2×105 cm-1；薄膜結構可由傅氏轉換紅外線光譜儀（Fouriertransform infrared, FTIR）知道鍵結密度。 最後應用於鈍化效果的本質層當中，其最高載子生命週期為808 sec，Vimplied為675 mV，復合速率約為18.5 cm/sec，並搭配奈米晶矽的摻雜層且製備出本質層為6 nm的異質接面太陽能電池（ITO/nc-p/i-SiC c-Si/i-SiC/nc-n），經過熱退火( Annealing )200 oC，2分鐘後的優化，利用太陽光模擬器量測其最高效率為12.7 %，Voc為594 mV。 This paper is based on electron cyclotron resonance chemical vapor deposition (ECR-CVD) to research the characteristics of amorphous hydrogenated silicon carbide (a-SiC:H) thin films and apply on heterojunction with intrinsic thin layer (HIT) solar cell. The HIT solar cell has recently reached a conversion efficiency of 23.0 % published from Sanyo. Because the interface passivation of hetero-interface would induce dangling bounds at the p-n junction, there will be recombination and then will reduce the charge carriers. Saturation of the dangling bonds at the surface is the main objective to suppress the recombination of charge carriers. Therefore, the short-circuit current (Jsc) of the solar cell will increase. Compared to the hydrogenated amorphous silicon (a-Si:H) thin film, a-SiC:H offers a higher thermal stability, a lower deposition rate, and the adjustability of the optical band gap over a wide range by the carbon incorporation. This behavior of the amorphous silicon carbide is attractive to applied on HIT solar cell. In this study, we investigate the influence of the variation of conditions on the properties of a-SiC:H thin films and surface passivation. Then we demonstrate the surface passivation for the fabrication of HIT solar cells. By using the optical emission spectroscopy and the ellipsometer, we can analyze the plasma and the optical characteristics of a-SiC:H thin films. It is shown that the absorption is lower than a-Si:H with a value 2×105 cm-1 at 400 nm. And the R* is 0.2 from the fouriertransform infrared analysis. Finally, the surface recombination velocity of a-SiC:H is about 18.5 cm/sec and the lifetime and the Vim are 808 sec and 675 mV, respectively. The application on HIT solar cell which the conversion efficiency can reach 12.7 %, and the open-circuit voltage can be improved to 597 mV.
