Progress in bulk GaN growth

Abstract

Three main technologies for bulk GaN growth, i.e., hydride vapor phase epitaxy (HVPE), Na-flux method, and ammonothermal method, are discussed. We report our recent work in HVPE growth of GaN substrate, including dislocation reduction, strain control, separation, and doping of GaN film. The growth mechanisms of GaN by Na-flux and ammonothermal methods are compared with those of HVPE. The mechanical behaviors of dislocation in bulk GaN are investigated through nano-indentation and high-space resolution surface photo-voltage spectroscopy. In the last part, the progress in growing some devices on GaN substrate by homo-epitaxy is introduced.

Layer-Scale and Chip-Scale Transfer Techniques for Functional Devices and Systems: A Review

“…One example of dry lift-off for layer release is LLO [ 180 , 181 , 182 , 183 , 184 , 185 , 186 , 187 ]. As schematically shown in Figure 1 b, LLO makes use of the difference in absorption of the laser light between the substrate and the layer being released.…”

“…Many investigations indicate that LLO can also be used for fabricating free-standing GaN substrates with large thickness [ 180 , 183 , 185 , 186 ]. The free-standing GaN wafer size by LLO was limited to 1.5~2 inches in earlier investigations [ 185 , 186 ], but 4-inch free-standing GaN wafers have been demonstrated recently [ 180 ]. Major factors preventing the achievement of large, thick GaN templates include cracks induced by the thermal strain relaxation and laser-induced shock waves, causing damage at the N-polar face of GaN.…”

“…It was reported that a heating plate above 800 degrees is helpful to release the compressive strain and avoid cracks during LLO. Laser spot size is another critical parameter affecting the laser-induced damage [ 180 ].…”

Room-Temperature Plasticity of a Nanosized GaN Crystal

“…Contemporary developments in GaN fabrication 55 are opening the way to appliances capable of outperforming Si-based products. They include nanocolumn LEDs, 13 the next generation of power-electronic devices, or wirelessly powered systems in autonomous cars.…”

“…Contemporary developments in GaN fabrication are opening the way to appliances capable of outperforming Si-based products. They include nanocolumn LEDs, the next generation of power-electronic devices, or wirelessly powered systems in autonomous cars. , Consequently, we are witnessing increased demand for all-embracing knowledge of the mechanical properties of GaN nanovolumes .…”