Highly conductive Ge-doped GaN epitaxial layers prepared by pulsed sputtering

作者：Ueno Kohei^*; Arakawa Yasuaki; Kobayashi Atsushi; Ohta Jitsuo; Fujioka Hiroshi

来源：Applied Physics Express, 2017, 10(10): 101002.

DOI：10.7567/APEX.10.101002

Highly conductive Ge-doped GaN epitaxial layers were grown by low-temperature pulsed sputtering, and their fundamental structural and electrical properties were investigated. The room-temperature (RT) electron concentration was increased to 5.1 x 10(20)cm(-3) by the Ge doping, and the atomically flat stepped and terraced surface and the crystalline quality of the layers were maintained. Consequently, the RT resistivity was reduced to 0.20m Omega.cm, which is comparable to that for typical transparent conductive oxides such as indium tin oxide. The contact resistance of Ge-doped GaN with a Ti/Al/Ti/Au metal stack prepared without annealing was as low as 0.087 Omega.mm. Furthermore, the selective formation of a Ge-doped region using an SiO2 mask was demonstrated. The results clearly indicate the strong potential of pulsed sputtering Ge-doped GaN growth for forming low-parasitic-resistance contact layers of various electrical and optical devices.

• 出版日期2017-10