Thermal Neutron Transmutation Doped Gallium Oxide Semiconductor Material

Recently, Galium Nitride (GaN) has become the topic of much research in building devices which can replace Silicon (Si) power devices particularly for use in high power high voltage applications with devices like MOSFETs (Metal Oxide Semi-Conductor Field Effect Transistors) and HEMTs, (High Electron Mobility Transistors). Gallium nitride is preferred due to its high bandgap energy, a high critical breakdown electric field, and a high thermal conductivity. These device applications rely on a thick (upwards of 180 μm) layers of N+ doped GaN. And, there has been an issue with several doping methods, especially while maintaining a doping consistent throughout the GaN layer.

Researchers at GW have developed a novel method for uniform Ge doping of GaN using the established method of Neutron Transmutation Doping (NTD) using low-energy neutrons. The beneficial effects of controlled and uniform doping of Ge via NTD are significant in terms of the future uses of that material in various high power electrical/electronic devices. They propose that employing GaN crystals grown with vanishingly small amounts of ¹⁴N and highly enriched in ¹⁵N, will allow for the NTD process of uniform Ge doping in GaN without the negative effects of Carbon (C) being introduced interstitially into the GaN lattice.

Applications:

• High power electrical/electronic devices
• Devices like MOSFETs (Metal Oxide Semi-Conductor Field Effect Transistors) and HEMTs, (High Electron Mobility Transistors)
• Light Emitting Diodes, (LEDs)

Advantages:

• Absence of any negative effects on GaN using ¹⁵N based material
• Ge-doped GaN should have properties superior to those of Si-doped GaN at high doping concentrations