Multi feed seed (MFS) high pressure crystallization of 1-2Â in GaN

The growth and physical properties of GaN crystallized in a multi feed-seed (MFS) configuration by High Nitrogen Pressure Solution (HNPS) growth method are presented in detail. The conversion of free standing HVPE-GaN crystals to free standing HNPS-GaN is the basis of the MFS configuration. The influence of the experimental conditions (i.e. growth temperature, temperature gradient, etc.), the c-plane bowing of the initial substrate, the electrical properties of HNPS-GaN, and the rate and mode of growth from solution are analyzed. We show that the HNPS-GaN crystals have better structural quality than their HVPE-GaN seeds. The defect density decreases with increasing growth temperature, reaching 5×105 cm−2 for crystals grown at 1420 °C or higher. In contrast, the free carrier concentration in HNPS-GaN increases with increasing growth temperature, reaching 7×1019 cm−3 for samples crystallized at 1440 °C. Thus the possibility to obtain good quality plasmonic GaN substrates for laser diodes can be realized.