複晶矽及複晶矽鍺薄膜中霍爾效應之研究

Abstract

電阻網路模型第一次被用來預測以超高真空化學氣相沉積系統所成長的複 晶矽及複晶矽鍺膜中之霍爾電壓並達到誤差5%以下之精確度, 研究中發現 不論對於複晶矽或複晶矽鍺的晶粒邊界缺陷密度均在10^12/每平方公分 至2*10^12/每平方公分之間, 這顯示以超高真空化學氣相沉積系統能成長 出高品質的複晶膜, 而且這些薄膜也非常適合作為偵測磁場的基本單元. 此外熱游離輻射理論能用來合理地解釋實驗中靈敏度隨輸入電流增加而遞 減的現象, 根據這些結果我們研究其在高解析電視系統上訊號讀取頭之應 用, 最後將提出一個可偵測磁場的三汲極薄膜電晶體之新穎結構. Hall voltages in Polycrystalline Si & SiGe(poly-Si and poly- SiGe)films grown by ultra-high vacuum chemical vapor deposition( UHV/CVD) had been predicted to the accuracy within 5% according to the Resistive-Network model for the first time. The grain bo- undary trap-state density,Nt,was found to be about 10^12/cm^2 ~ 2*10^12/cm^2 for both poly-Si and poly-SiGe films indicated that the quality of these UHV/CVD-grown films is extremely high. We also found that these films are suitable Hall elements to sense gnetic field. Experimental results show that the sensitivity decreased with increasing input current, which can be well expl- ained using the thermionic emission theory. Based on these resu- lts,we will study the application for High Definition Television (HDTV) used magnetic head. Finally,a novel structure of triple- drain magnetic thin film transistor(TFT) was proposed.