GAN POWER RECTIFIERS AND FIELD-EFFECT TRANSISTORS ON FREESTANDING GAN SUBSTRATES

摘要

There are emerging applications for GaN and electronics in control and switching of electric power in the utilities industry, advanced radar sub-systems, and in the drive-trains of hybrid electric vehicles. The key components of the inverter modules for such applications are the power rectifier and transistor. P-i-n rectifiers were fabricated on epitaxial layers grown on free-standing GaN substrates. The forward turn-on voltage was ～5 V at 300 K and displayed a positive temperature coefficient. The specific on-state resistance was ～5 mΩ·cm~2 at 300 K. The figure-of-merit was 0.32 MW-cm~(-2). The reverse recovery time was ≤ 600 ns at 300 K. A comparison of the DC and pulsed characteristics of AlGaN/GaN HFETs on both GaN and Al_2O_3 substrates before and after Sc_2O_3 passivation was performed. HFETs on GaN substrates show less electron accumulation in the gate-drain surface region than do comparable devices on substrates.