Deep trap-induced dynamic on-resistance degradation in GaN-on-Si power MISHEMTs

• Trap spectroscopy performed on GaN MISHEMTs during high voltage switching.
• Single trap (EC − 2 eV) linked to on-resistance degradation during high voltage switching.
• Trap spectroscopy on capacitance test structures confirmed location in GaN buffer.
• Localized high-field charging of EC − 2 eV trap in MISHEMT degrades on-resistance.

Identification and characterization of a single, deep trap causing large increases in the on-resistance of GaN-on-Si power metal-insulator-semiconductor-high electron mobility transistors (MISHEMTs) is reported. This is achieved by using HEMT-based deep level optical spectroscopy (DLOS) and related methods in conjunction with high voltage off-state VDS switching up to 400 V. A trap with an activation energy of ~ EC − 2 eV that is physically located in the drain-access region of the MISHEMT is shown to be the primary source of an increase of the dynamic on-resistance increase by as much as ~ 9 times at 400 V operation. Comparisons of trap signatures extracted from the MISHEMT with capacitance-based DLOS measurements of simple Schottky-diode test-structures showing the same, dominant trap signature suggests that the physical defect is located within the GaN buffer and is not a surface or insulator-related defect. A buffer trap based model is presented to explain the observed on-resistance degradation effects in the MISHEMTs during high voltage switching.