p型金氧半電晶體反轉層電洞遷移率的物理計算

Abstract

在過去的數十年中，為了追求高積集度、高速度、以及低功率消耗的元件表現，互補式金氧半場效電晶體的元件尺寸不斷地被縮小。此篇研究論文的目的是根據元件量子物理的觀念，針對一個p型的金氧半場效電晶體，在其形成反轉層時對等效的電洞遷移率建立了一個簡單的計算模型，並將程式模擬的結果和”普適曲線”的實驗結果做比較。 較詳細的次能帶結構計算可以由k∙p的方法求解一維的薛丁格和波松方程式得到。而在我們的模型裡面，我們使用了求解4×4 Luttinger-Kohn矩陣的特徵值的方法來得到修正過的次能帶結構。除此之外，我們使用了等效質量的模型分別去推算量子化等效質量、能態密度等效質量以及導電度等效質量。 我們考慮了三個散射模型:聲學聲子散射、光學聲子散射和表面粗糙度散射。最終，我們建立了一個等效的電洞遷移率模型並將結果和Takagi教授在不同溫度下的實驗結果做比較。

In pursuit of high integration density, high speed and low power consumption, complementary metal-oxide-semiconductor (CMOS) devices have been undergoing a progressive down-scaling strategy over the past few decades. The purpose of our study is to build a simple hole mobility model in the inversion layer of a p-type metal-oxide-semiconductor field effect transistor (pMOSFET) based on quantum device physics and compare the results with the experimental data on the so called universal curves. A detailed subband structure calculation is obtained by solving the one-dimensional Schrodinger and Poisson equations with a six-band k•p procedure. In our model, however, we have used a modified subband structure which is actually the solution of the eigenvalue problem in a 4×4 Luttinger-Kohn matrix. Besides, we have also used an equivalent effective mass model to derive the quantization-direction effective mass, the density-of-states effective mass, and the conductivity effective mass. Three scattering mechanisms are included in our model: acoustic phonon scattering, optical phonon scattering, and surface roughness scattering. Finally, we build a modified hole mobility model and compare the calculation results with Takagi’s data for various temperatures.