雙閘極金氧半場效電晶體模擬器

Abstract

隨著元件尺寸的縮減，短通道效應所造成的影響，已成為不可忽略的問題之一。為了解決此問題，多種方法相繼被提出，其中之一即為多閘極場效電晶體的結構，也是現今熱門話題。本篇論文主旨為利用薛丁格和波松方程式自洽及相關物理模型來建立一雙閘極金氧半場效電晶體模擬器，進而幫助我們來了解此結構的相關物理特性。此外，很多的模擬器在解薛丁格和波松方程式自洽時，常常將矽基板和氧化層界面的位能當作無限大來做運算，但真實的矽基板和氧化層界面的位能並不是無限大而是幾電子伏特而已，因此波函數穿隧到氧化層的效應應該被考慮。有鑒於此，我們也將波函數的穿隧效應加入到我們的模擬器中，並討論了穿隧效應的影響及不同的電子穿隧質量對雙閘極場效電晶體所造成的變化。最後，我們也建立了載子遷移率及應力模型來與相關文獻做比較。由比較結果來看，除了在載子遷移率方面還需考慮更多的散射機制外，不論是否有考慮穿隧效應，我們的模擬器都和Schred軟體及相關論文結果相符，具有一定的準確性。

It is well known that the scaling of the traditional bulk MOSFETs would encounter several issues like the short channel effects (SCE). To deal with this problem, many of methods have been proposed, one of which is new device architectures, such as multi-gate structures. The aim of this work is to develop a double-gate n-MOSFET simulator by using self-consistent solving of Schrödinger and Poisson equations with some physical models taken into account. Besides, for many simulators in the literature, the boundary conditions of Schrödinger’s equation are often making an infinite potential barrier height at the silicon/gate-oxide interface. Nevertheless, we know that the actual barrier height is finite and is equal to a few electron-volts. Therefore, wave-function actually can penetrate into the gate-oxide dielectric. Hence, we also add wave-function penetration effect to our simulator, and discuss the influences of penetration effect and electron tunneling effective mass on the double-gate structure performance. Finally, we also build mobility and stress related model, and compare those with literature values. From the comparison results, our simulations are consistent with Schred as well as with some articles with and without wave-function penetration included, except for the mobility of thinner substrate thickness which should consider more scattering mechanisms. That is to say, our simulator comes to be reasonable for calculating fundamental properties in DG n-MOSFETs.