Effective passivation of defects in Ge-rich SiGe-on-insulator substrates by A1_2O_3 deposition and subsequent post-annealing

摘要

A method of Al_2O_3 deposition and subsequent post-deposition annealing (A1_2O_3-PDA) was proposed to passivate electrically active defects in Ge-rich SiGe-on-insulator (SGOI) substrates, which were fabricated using Ge condensation by dry oxidation. The effect of A1_2O_3-PDA on defect passivation was clarified by surface analysis and electrical evaluation. It was found that A1_2O_3-PDA could not only suppress the surface reaction during Al-PDA in our previous work [Yang H, Wang D, Nakashima H, Hirayama K, Kojima S, Ikeura S. Defect control by Al-deposition and the subsequent post-annealing for SiGe-on-insulator substrates with different Ge fractions. Thin Solid Films 2010; 518: 2342-5.], but could also effectively passivate p-type defects generated during Ge condensation. The concentration in the range of 10~(16)-10~(18)cm~(-3) for defect-induced acceptors and holes in Ge-rich SGOI drastically decreased after A1_2O_3-PDA. As a result of defect passivation, the electrical characteristics of both back-gate p-channel and n-channel metal-oxide-semiconductor field-effect transistors fabricated on Ge-rich SGOI were greatly improved after AI_2O_3-PDA. 【Keywords】SiGe-on-insulator;Ge condensation;AI_2O_3-PDA;Defect passivation;Hole concentration;Acceptor concentration;MOSFET;