鍺通道超薄絕緣層負電容金氧半場效電晶體之設計空間及負電容鰭狀電晶體之鰭邊緣粗糙引發之變異度分析

Abstract

本篇論文探討了超薄絕緣層異質鍺通道負電容金氧半場效電晶體之設計空間，通道材料之介電常數與內建之等效基極偏壓效應(尤其對於鍺通道P型電晶體)為兩個主要影響負電容場效電晶體之設計的因素，較高的通道介電常數增強通道內部之垂直方向電場以及水平方向汲極產生的電場，因而造成高介電常數材料如鍺會有更大的負電容場效電晶體設計空間。然而，正向的內建之等效基極偏壓效應卻會壓縮鍺通道P型電晶體的負電容場效電晶體設計空間。 除此之外，我們也研究了負電容鰭狀電晶體的本質變異度。負電容鰭狀電晶體對於鰭邊緣粗糙引發之變異度是較輕微的，因為負電容具備的反饋機制，此反饋機制的來源為電壓放大效果及此效果與短通道效應之正向關聯性。另外通道表面電荷缺陷之數量與位置對於負電容鰭狀電晶體之效用也較微弱，因為負電容反饋機制以及負電容引發的較薄等效柵極氧化層。

In this thesis, we first investigate the design spaces for hetero-channel Ge UTBB NCFET. The results show the channel permittivity difference and the effective built-in back gate bias which is significant for Ge pFET are two primary factors that affect the UTBB NCFET design space. The higher permittivity channel that enhances the vertical field and increases the short channel effects is a superiority for UTBB NCFET design. On the other hand, the forward effective built-in back gate bias may degrade the UTBB NCEFT design spaces for the p-type Ge-channel UTBB NCFET comparing to the n-type Ge-channel counterparts. Besides the device design space, we also investigate the NC-FinFET intrinsic variability. The NC-FinFET exhibits superior immunity toward Fin-LER induced variabilities due to the negative capacitance feedback mechanisms including the amplification effect as well as the relation between short channel effects and the voltage gain. Furthermore, the trap position and number induced variabilities are also suppressed in NC-FinFETs. The suppression results from the negative capacitance feedback mechanism and the negative capacitance reduced effective oxide thickness for NC-FinFETs.