绝缘层上单轴应变硅的应力计算与分析

Stress calculation and analysis of uniaxially strained silicon on the insulator

为了研究晶圆级绝缘体上单轴应变硅的应力分布与应力变化趋势,首先利用绝缘体上硅晶圆在机械弯曲状态下退火的工艺,成功制作了绝缘层上单轴应变硅晶圆,其优点是工艺简单、成本低、应变量高.应用ANSYS仿真软件,重点对不同弯曲半径、不同晶向的机械致绝缘层上单轴应变硅晶圆的应力情况进行了模拟计算.模拟结果表明,应力随弯曲半径的减小而显著增加,且沿弯曲方向的应力最大,适于作为应变互补金属氧化半导体器件的沟道方向,但应力分布的均匀性会随弯曲半径的减小而略有下降.最后利用光纤光栅法对制备的绝缘层上单轴应变硅晶圆的应力分布进行了测量,其结果与ANSYS模拟结果吻合,证明了ANSYS模拟分析的准确性.

In order to study the wafer level uniaxial strained silicon insulation layer on the stress distribution and variation trend, a uniaxial strained SOI wafer is successfully fabricated by annealing in SOl mechanical bending at the wafer level, with the advantages of low cost and simple process. On this basis, the stress of mechanical induced uniaxially strained SOI wafers in various directions under different bending radii is simulated with ANSYS, and the results show that the stress along the bending direction, which is suitable for the channel of the COMS device, is much larger than that perpendicular to the bending direction. Also, the stress significantly increases and the uniformity of the stress distribution decreases with the decrease of bending radii. The stress distribution of the uniaxially strained SOI obtained by the optical fiber grating measurement is in good agreement with the ANSYS simulation results.