Thermal Stability Of SiGe/Si Quantum Well Structures Grown By APCVD

Abstract

AbstractSingle and double Si1-xGexx/Si quantum well (QW) structures, which were grown by atmospheric pressure chemical vapor deposition (APCVD), are characterized by photoluminescence and secondary ion mass spectrometry. Systematic post-growth annealing treatments were carried out at temperatures between 600°C and 1100°C in pure N2 ambient. The interdiffusion between the Si layer and the Si1-xGex, well layers occurs at the annealing temperature around 900°C. The diffusion coefficient is deduced at different temperatures from SIMS measurements for single QW structures. The activation energy is about 3.9 eV in the temperature range between 950°C and 1100°C. The double QW structures show a similar value, but the accurate value is more difficult to obtain because it is more complicated to analyze the SIMS profile of the double QW structures. The intensity of the exciton recombination related to carriers confined in the double QW structures decreases with increasing annealing temperatures and becomes strongly suppressed at 750°C. When the annealing temperature is increased further, the intensity of the QW emission recovers. The results indicate that nonradiative centers were generated at annealing temperature of about 750°C