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HL: Fachverband Halbleiterphysik

HL 96: Poster III C (III-V Semiconductors incl. Nitrides)

HL 96.7: Poster

Donnerstag, 19. März 2015, 14:00–20:00, Poster B

Oxygen and hydrogen profiles and electrical properties of unintentionally doped n-GaN grown by HVPE — •Valentin Garbe^1,2, Barbara Abendroth¹, Hartmut Stöcker¹, Arkadi Gavrilov², Doron Cohen-Elias², Shlomo Mehari², Dan Ritter², and Dirk C. Meyer¹ — ¹Institute for Experimental Physics, TU Bergakademie Freiberg, Leipziger Str. 23, 09599 Freiberg, Germany — ²Department of Electrical Engineering, Technion, Israel Institute of Technology, Haifa 32000, Israel

During hydride vapor phase epitaxy (HVPE) growth of GaN, oxygen and hydrogen are easily incorporated. Oxygen is an n-type dopant, while hydrogen may passivate some of the donors. In this work, we attempt to characterize commercially available 5 µm thick HVPE grown (0001) GaN (deposited on sapphire), which is unintentionally n-doped. On the basis of secondary ion mass spectrometry profiles provided by the manufacturer Kyma Inc., electrical (capacitance–voltage, Hall), structural (high resolution X-ray diffraction) and optical (polarized infrared spectroscopy) methods were utilized to derive a GaN layer model of the wafer, including doping profile and mobility. The model contains two different layers, a smooth GaN surface layer which exhibits lower carrier concentration but higher mobility, while a bottom layer shows higher background carrier concentration and lower mobility, because of high impurity incorporation. Oxygen seems to be the donor, substitutionally filling the positions of nitrogen vacancies, leading to the overall n-doping. Surprisingly, the effect of hydrogen passivation seems to play no role here.