超薄絕緣鍺金氧半場效電晶體在量子侷限下的短通道效應模型與分析

Abstract

鍺作為通道材料已被提出可以提供更高的載子遷移率。然而，它的高介電常數造成其非常易受到短通道效應的影響。為了改善靜電完整性，有著薄埋層氧化層的超薄絕緣鍺金氧半場效電晶體被視作一個有希望的元件結構以繼續CMOS的微縮。在本論文裡，我們理論化地探討在超薄絕緣鍺金氧半場效電晶體中量子侷限效應對臨界電壓衰變的衝擊。為了獲得臨界電壓，我們解析Schrödinger方程式且根據一個拋物線形式的通道電位來導出量子侷限模型。這拋物線形式的通道電位是從解Poisson方程式得到的通道電位級數解簡化得來，且此級數解有正確的通道長度依靠性。因此，我們的量子侷限模型可以用來檢驗超薄絕緣鍺元件的短通道效應。我們的研究指出對於極限微縮的超薄絕緣鍺元件，臨界電壓衰變可以被量子侷限給壓制。

Germanium as a channel material has been proposed to enable mobility scaling. However, its high permittivity makes it very susceptible to short-channel effects (SCEs). To improve the electrostatic integrity, ultra-thin-body (UTB) germanium-on-insulator (GeOI) MOSFET with thin buried oxide has been proposed as a promising device architecture to continue CMOS scaling. In this thesis, we theoretically investigate the impact of quantum-mechanical effects on the threshold-voltage ( ) roll-off in UTB GeOI MOSFETs. To obtain , we have analytically solved the Schrödinger equation and derived a quantum-confinement model based on a parabolic form of channel potential. This parabolic channel potential is simplified from the series solution of Poisson’s equation and has the correct dependence of channel length. Therefore, our quantum-confinement model can be used to examine the SCEs for UTB GeOI devices. Our study indicates that for extremely-scaled UTB GeOI devices, roll-off can be suppressed by quantum confinement.