Stefan Eichler

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

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.

Vertical Bridgman Growth of Binary Compound Semiconductors

Abstract This chapter gives an overview of the state of the art of Bridgman methods for the crystal growth of binary compound semiconductors. The development of the growth equipment and growth technologies are outlined. In particular, the distinctive features such as liquid encapsulation, use of boron nitride crucibles, options of flow control in the melt, twin formation during facet growth, doping and segregation of dopants, dislocation behavior, and formation of precipitates and inclusions are summarized. The focus of the description is on the most prominent materials for III-V compounds (GaAs) and II-VI compounds (Cd1−xZnxTe). A selected bibliography is given to deepen the matter.