Strain Engineering for Germanium-on-Insulator Mobility Enhancement with Phase Change Liner Stressors
Yan-Yan Zhang1, Ran Cheng1, Shuang Xie2, Shun Xu1, Xiao Yu1, Rui Zhang1, Yi Zhao1,2**
1College of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027 2State Key Lab of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027
Abstract：We investigate the strain in various Ge-on-insulator (GeOI) micro-structures induced by three phase-change materials (PCMs) (Ge$_{2}$Sb$_{2}$Te$_{5}$, Sb$_{2}$Te$_{3}$, GeTe) deposited. The PCMs could change the phase from amorphous state to polycrystalline state with a low temperature thermal annealing, resulting in an intrinsic contraction in the PCM films. Raman spectroscopy analysis is performed to compare the strain induced in the GeOI micro-structures by various PCMs. By comparison, Sb$_{2}$Te$_{3}$ could induce the largest amount of tensile strain in the GeOI micro-structures after the low temperature annealing. Based on the strain calculated from the Raman peak shifts, finite element numerical simulation is performed to calculate the strain-induced electron mobility enhancement for Ge n-MOSFETs with PCM liner stressors. With the adoption of Sb$_{2}$Te$_{3}$ liner stressor, 22% electron mobility enhancement at $N_{\rm inv}=1\times10^{13}$ cm$^{-2}$ could be achieved, suggesting that PCM especially Sb$_{2}$Te$_{3}$ liner stressor is a promising technique for the performance enhancement of Ge MOSFETs.
2017, Vol. 34 
