Silicon doping of HVPE GaN bulk-crystals avoiding tensile strain generation

Abstract

Doped GaN:Si crystals were grown in a commercially available vertical HVPE reactor. The templates used for the HVPE heteroepitaxy were so-called FACELO seeds, with a starting GaN layer thickness of 3–4 μm. The FWHM of the 0002 and the reflection of the HVPE-grown GaN:Si crystals with a thickness of 3 mm are and , respectively, indicating excellent crystal quality. Hall measurements resulted in a charge carrier concentration of cm−3, while exhibiting a mobility of 250 cm−2V−1 s−1. These values coincide with the values extracted from FTIR measurements and the lineshape fitting of the A1(LO)/plasmon coupled phonon mode of the confocal Raman measurements. SIMS investigations yielded a silicon atom concentration of cm−3. This indicates an activation of the dopant atoms of approximately 90%. The TDD determined by CL dark spot counting was cm−2. Within the measurement accuracy, the confocal Raman measurements did not show a tensile strain generation due to the silicon doping with resulting charge carrier concentrations of cm−3.