[15a-A21-1~11] 15.4 III-V-group nitride crystals

△ [15a-A21-10] Infrared Reflectance Spectroscopy of Free-standing GaN Bulk Substrates

〇Kazutaka Kanegae¹, Kaneko Mitsuaki², Kimoto Tsunenobu², Horita Masahiro², Suda Jun² (1.Kyoto Univ., 2.Dept. of Electron. Sci. & Eng., Kyoto Univ.)

Keywords:GaN, infrared reflectance spectroscopy

Carrier concentration and mobility can be estimated by measuring longitudinal optical phonon-plasmon coupling mode by infrared reflectance spectroscopy or Raman scattering spectroscopy. These methods can be used to inspect wafers and to evaluate the in-plane distribution as a nondestructive, contactless and facile method. There are many studies on infrared reflectance spectroscopy of GaN, however, most of them are of GaN grown on sapphire. In general, such GaN layers contain high density of threading dislocations as well as large residual strain, at which precise analysis is difficult. Recently, high-quality free-standing GaN substrates are available. In this study, we investigated high-quality free-standing n-type GaN (0001) substrates with different carrier concentrations to verify general analysis method of infrared reflectance spectra.