Recent Advances in III-Nitride Devices Grown on Lithium Gallate

Abstract

Recent advances in the growth of III-nitride materials and devices include: (i) The reduction of the near-surface threading dislocation density in GaN on lithium gallate (LGO) to ≈2 × 107 cm—2. (ii) The demonstration of GaN, 50 × 130 μm, metal–semiconductor–metal (MSM) photodiodes with extremely low leakage current, 0.11 pA at 2 V and 7.9 pA at 60 V, and UV photoresponse at 308 nm and 20 V of 0.105 A/W. (iii) State of the art MSM devices have been successfully removed from the LGO substrate and attached to silicon wafers with no degradation in current characteristics. (iv) Demonstration of very thin, 0.7 μm HFET structures, grown at a rapid rate of 0.9 μm/h, with near state of the art room temperature 2DEG mobilities of 1365 cm2/Vs at a sheet charge of 9 × 1012 cm—2. (v) The elimination of substrate impurity diffusion by inclusion of gettering buffers has also been demonstrated.