STemperature effect of metal contacts on GaN

摘要

The effect of measurement temperature on n-type ohmic contacts, Schottky diodes, MOS diodes, and GaN MOSFETs were investigatd. The thermionic current transort reduced the specific contact resistivity of Au/Ti based metallization on n-GaN at elevated measurement temperature, however, at higher temperature (>250 deg C) the total contact resistance increased due to the increase of metal resistance. Analysis of the effect of temperature on the device shows that gate leakage is significantly reduced at elevated temperature relative to a Schottky diode. Ga_2O_3(Gd_2O_3) was used on GaN as a gate dielectric for a depletion metal oxide semiconductor field effect transistor (MOSFET). Device characteristics in fact improved upon heating to 400 deg C. Modeling of the effect of temperature on contact resistance suggests that the improvement is due to a reduction in the parasitic resistances present in the device.