Abstract
In this article, we report on the single pulse charge pumping (SPCP) measurements as a method to extract the interface trap density (Nit) on the GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs). The electron capture and emission processes are monitored in the time domain and studied during the rising and falling edges of a gate voltage pulse. Two different gate stacks are studied by SPCP including epitaxial Mg 0.25 Ca 0.75 O (MgCaO) and amorphous Al 2 O 3 . The signature charge pumping (CP) current peaks are observed enabling a direct extraction of Nit as low as 1.4 × 10 11 cm -2 with gate voltage sweeping from OFF-state to ON-state in the GaN MOS-HEMT with epitaxial MgCaO gate stack. A significant reduction of Nit by the MgCaO gate stack compared to Al 2 O 3 only gate stack is also confirmed by the SPCP method. SPCP realizes a direct Nit measurement on GaN transistors and confirms the high quality interface between the single crystalline epitaxial MgCaO and GaN. It is verified as a fast and reliable interface characterization method on III-V HEMTs, gate-all-around nanowire transistors, and 2-D transistors, which do not exhibit body contacts as the conventional Si transistors needed for conventional CP measurements.