High responsivity lateral GaN film photoconductive semiconductor switch based on sapphire substrates for high-power application

Gallium nitride (GaN) materials have high absorption coefficient and wide bandgap. In this work, an excellent ohmic contact electrode with low specific contact resistivity of 5.9 × 10^-6 Ω·cm² is prepared on semi-insulating GaN material grown by MOCVD. Moreover, the high-responsivity lateral GaN photoconductive semiconductor switch (PCSS) is developed on a GaN film with a thickness of only 2.5 microns at a laser trigger having a wavelength of 355 nm. For the GaN PCSS with an electrode gap of 3 mm, when the input voltage is 10 kV and the laser energy is 2 mJ, the output peak current reaches 137.6 A and the responsivity is up to 5 × 10^-4 A/W. The results of experiment and simulation could prove that the silicon ion implantation improves the ohmic contact quality of the device, regulates the electric field distribution during on-state, and reduces the peak electric field.