Influence of the ZrO2 gate dielectric layer on polarization coulomb field scattering in InAlN/GaN metal–insulator–semiconductor high-electron -mobility transistors

An InAlN/GaN MIS-HEMT with ZrO2 gate dielectric layer and a Schottky-gate InAlN/GaN HEMT were fabricated. Subsequently, the influence of ZrO2 gate dielectric layer on polarization Coulomb field (PCF) scattering in InAlN/GaN MIS-HEMT was studied. Compared with InAlN/GaN HEMT, the ZrO2 gate dielectric layer in InAlN/GaN MIS-HEMT results in fewer additional polarization charge and higher two-dimensional electron gas density at the same gate-source voltage (VGS) conditions. Also, we established that both of these factors weaken PCF scattering intensity. However, the InAlN/GaN MIS-HEMT has a larger gate swing. Therefore, there is a smaller VGS was applied during regular operation of device. When the VGS is small, PCF scattering is the strongest scattering and play non-negligible impact in the size of total electron mobility. This study provides a new theoretical foundation for further enhancing the performance of InAlN/GaN MIS-HEMTs. •The influence of the ZrO2 gate dielectric layer on PCF scattering in InAlN/GaN MIS-HEMTs was determined.•The ZrO2 layer leads to fewer ΔρG and higher n2DEG at the same gate bias conditions, both of these factors weaken PCF scattering intensity.•When the gate bias is small, PCF scattering plays a dominant role in the magnitude of the total electron mobility.•The results of this study have providing a new theoretical basis for further enhancing performance of InAlN/GaN MIS-HEMTs.