Highly strain-relaxed ultrathin SiGe-on-insulator structure by Ge condensation process combined with H+ irradiation and postannealing

Abstract

Strain-relaxation process of SiGe-on-insulator (SGOI) structures in the oxidation induced Ge condensation method has been investigated as a function of the SiGe thickness. Complete relaxation was obtained for thick SGOI layers (>100nm). However, the relaxation rates abruptly decreased with decreasing SiGe thickness below 50nm, i.e., the relaxation rate of 30% at 30nm SiGe thickness. In order to improve this phenomenon, a method combined with H+ irradiation with a medium dose (5×1015cm−2) and postannealing (1200°C) has been developed. This successfully achieved the high relaxation rate (70%) in the ultrathin SGOI (30nm).

Comprehensive study of low temperature (< 1000 °C) oxidation process in SiGe/SOI structures

“…High temperature oxidation (N1100°C) process is usually used to induce Ge condensation process of SiGe/SOI structures, which is employed to fabricate strained Si on SGOI [4][5][6][7]. On the other hand, low temperature oxidation (b1000°C) process of SiGe has not been clarified yet, even though it is used as isolation process of SiGe devices as reported by Nishisaka et al [8].…”

Influences of Si pillar geometry on SiN-stressor induced local strain

“…Precise control of strains is necessary for such fabrication. The strained Si can be formed by the global strain technique in which Si layers are epitaxially grown on relaxed SiGe buffer layers on insulator (SGOI) structures [1][2][3][4]. This technique can control the strains in strained Si by tuning the Ge fraction of the SGOI; however, it cannot be applied to 3D microstructures, such as vertical type CMOSs.…”

Experimental evidence of oxidant-diffusion-limited oxidation of SiGe alloys

“…Several studies focused on the issue that the oxide growth rate was enhanced with respect to pure Si under different conditions, 4-6 while many other authors were interested in the strain relaxation processes of SiGe layer. [7][8][9] Some researches investigated the accumulation and diffusion of Ge atoms during the oxidation process. 10,11 In addition, several models were proposed to explain the oxidation kinetics of SiGe.…”