Low 1/f noise in AlGaN/GaN HFETs on SiC substrates

Experimental results of the low-frequency noise measurements on a large num ber of different AlGaN/GaN High Electron Mobility Transistors (HEMTs) grown on sapphire and SIC substrates have been presented. In the HEMTs grown on sapphire, the 1/f noise is an order of magnitude (or more) higher than for AlGaN/GaN HEMTs grown on SiC substrates. The devices on SIC substrates also have higher electron mobility compared to the devices grown on sapphire su bstrates. The temperature dependence of noise reveals a contribution to the noise from a local level with activation energy of approximately 0.42 eV f or the structures grown on sapphire. A very weak temperature dependence of the low-frequency 1/f noise found for the wafers grown on SiC is very impor tant for high temperature applications of these devices.