Temperature-Dependent Microwave Noise Characteristics in ALD Al 2 O 3 /AlGaN/GaN MISHEMTs on Silicon Substrate

Temperature-dependent microwave noise character- istics are presented in an atomic-layer-deposited Al2O3/AlGaN/ GaN metal-insulator-semiconductor high-electron mobility tran- sistor (HEMT) (MISHEMT) on a Si substrate over a wide temper- ature range from −40 ◦ C to 200 ◦ C. Typical noise parameters, including minimum noise figure ( NF min), noise equivalent re- sistance (Rn), and associate gain (Ga), are measured over the whole temperature range. The conventional Schottky-gate HEMT with the same epistructure is also compared. The temperature dependences of NF min and Rn for the MISHEMT are found to be similar to those for the conventional HEMT, respectively, whereas less temperature dependence of Ga is found in the GaN MISHEMT. The degradation rate of the noise performance of MISHEMT is found to be comparable to that of the other reported GaN HEMTs on SiC and sapphire substrates and also comparable to that of GaAs HEMTs. Index Terms—Al2O3, GaN, metal-insulator-semiconductor high-electron mobility transistor (HEMT) (MISHEMT), noise, temperature dependence.