Two inch GaN substrates fabricated by the near equilibrium ammonothermal (NEAT) method

Abstract

This paper reports two inch gallium nitride (GaN) substrates fabricated from bulk GaN crystals grown in the near equilibrium ammonothermal method. 2 GaN wafers sliced from bulk GaN crystals have a full width half maximum of the 002 X-ray rocking curve of 50 arcsec or less, a dislocation density of mid-105 cm−2 or less, and an electron density of about 2 × 1019 cm−3. The high electron density is attributed to an oxygen impurity in the crystal. Through extensive surface preparation, the Ga surface of the wafer shows an atomic step structure. Additionally, removal of subsurface damage was confirmed with grazing angle X-ray rocking curve measurements from the 114 diffraction. High-power p–n diode structures were grown with metalorganic chemical vapor deposition. The fabricated devices showed a breakdown voltage of over 1200 V with sufficiently low series resistance.