Photoluminescence evaluation of defects generated during SiGe-on-insulator virtual substrate fabrication: Temperature ramping process

Abstract

Crystal qualities of Si∕SiGe∕Si-on-insulator structures with different SiGe thicknesses were evaluated by photoluminescence (PL). The wafers were annealed at different temperatures with a ramping rate of 5°C∕min. Free exciton PL peaks were clearly observed for the as-grown wafers and decreased with an increase in the annealing temperature. For the annealed wafers, defect-related PL signals were observed at around 0.82, 0.88, 0.95, and 1.0eV, which varied according to the annealing temperature and the SiGe thickness. They were also correlated to dislocation-related defects by transmission electron microscopy.

Defect control by Al deposition and the subsequent post-annealing for SiGe-on-insulator substrates with different Ge fractions

“…Thus, high N A should also originate from the DB's induced by the structural defects of SF generated during the structural change from SiGe-on-SOI to SGOI at the initial stage of Ge condensation due to strain relaxation [4].…”

“…However, strain relaxation may occur accompanied by the generation of stacking-fault (SF) defects during the structural change from SiGe-on-SOI to SGOI at the initial stage of Ge condensation [4]. With an increase in Ge%, defects such as threading dislocations [5], SFs and microtwins [6,7] were also observed owing to the strain relaxation.…”

Defect Evaluation by Photoluminescence for Uniaxially Strained Si-On-Insulator

“…4,10 The detailed composition of D3/D4 was studied by changing laser power, as shown in Fig. 4 We found that D3/D4 peaks generated at low thermal-treatment temperatures and D1/D2 peaks appeared at thermal-treatment temperatures higher than 950 • C, simultaneously D3/D4 peaks disappeared. The red-end of defect-related PL spectra rapidly saturated with increasing laser power, while the blueend also showed a saturation tendency, implying a relatively-low defect density (note the maximum laser power was only 4 mW).…”

“…4,10 The detailed composition of D3/D4 was studied by changing laser power, as shown in Fig. In this energy region, the well-known dislocation-related PL signals D3 (0.934 eV) and D4 (1.000 eV) exist, which are due to straight misfit dislocations.…”

Defect-Induced Deep Levels in SiGe-on-Insulator Substrate Fabricated using Ge Condensation Technique

“…It should be also noted that the initial SGOI showed almost complete lattice relaxation. This means that strain relaxation should occur during the structural change from SiGe-on-SOI to SGOI at the initial stage of Ge condensation, resulting in SF defect generation, which has been clearly observed in photoluminescence measurements [6].…”