A comparative study on AlGaN/GaN based HEMT and MIS-HEMT with Al_2O_3 as gate dielectric

摘要

The critical issue which limits the operations of GaN based HEMTs is their high gate leakage which is undesirable for high power and low noise applications. To overcome this gate leakage study on MIS-HEMT are necessary. We demonstrate a simple synthetic route for Al_2O_3 formation as dielectrics for AlGaN/GaN based MIS-HEMTs which is also compatible with the device process. 10 nm Aluminum layer was oxidized using oxidative annealing technique at 600℃ for 15 minutes at Oxygen ambient. The device characteristics of HEMT and MIS-HEMTs were studied. The I_(d max) observed at a gate bias of 2 V for HEMT and MIS-HEMTs were 593 and 425 mA/mm respectively. The g_(m max) measured for HEMTs and MIS-HEMTs were 124 and 121mS/mm. The gate leakage was reduced three orders of magnitude for MIS-HEMTs compared to the HEMTs. Three terminal off state breakdown measurements were performed for both the devices. The suppression of gate leakage by three orders for MIS-HEMTs accompanied an increase in breakdown voltage (BV). The BV for HEMTs and MIS-HEMTs were 170 and 207 V respectively. Further the interface quality of dielectric and semiconductor interface is under investigation.