Strain Silicon Band And New Silicon Mos Device Structure Research

About fifty years ago, Gordon Moore, the co-founder and Chairman Emeritus of Intel Corporation, authored that the numbers of ICs per mm2will be doubled at every18months, which respected as Moore’s Law. In industry, scaling down is used to improve the integrated circuit performance. But in fact, due to the various of parasitic effect can not be scaled down, the performance of integrated circuit is suppressed by short channel effect, high field effect, quantum effect, which seems the Moore’s Law is broken. So many efforts are to recover it, and Strained silicon (SSi) technology is a useful and necessary method implemented by advance nano-device, who amends silicon energy band structure, so as to reduce carrier’s scattering probability and effective mass, so as to raise its mobility, actually enchance device’s performance.This paper is primarily concerned the relationship between stress and strain in silicon, the correlation between stress direction, size and the modification of silicon band structure, the influence of STI inclination on stress distribution and device performance and the new stress introduction technique.Firstly, according to Hooker’s Law, the relationship between the lattice parameters of SSi and stress is analysised for (100),(110) and (111) surface. Based on First Principle theory, band structure of SSi is calculated. Then the relationship of stress and band structure is discussed.Secondly, STI inclination varying in actual STI stress introduced process is focused, and the effect of STI inclination on the electrical performance of Nano-MOS devices by theoretical analysis and finite element simulation is performed for the first time. The optimization value a=105°have been obtained.Finally, based on the characteristic of silicon oxidation volumetric expansion2.2times, a new method of introducing stress is come up with, then a concept of temperature time product (TT) by analysis of stress transmission paths, the effect of temperature and time on stress is expressed, and it is included for H2O oxidation that the smaller TT is, the higher stress is obtained. Based on it, PolySilicon (PoS) oxidation process conditions are optimized. Meanwhile, the PoS oxidation induced about2GPa tensile stress is validated by PoS oxidation experiment.