Threshold Voltage Modulation Engineering Using p-Type CuO and NiO for the AlGaN/GaN Enhancement-Mode Fin-MOS-HEMTs on the Si Substrates

This work presents the threshold voltage modulation of the thin-barrier Al0.45Ga0.55N/GaN Fin-metal oxide semiconductor-high electron mobility transistors (MOS-HEMTs) with two types of p-type metal oxide (CuO and NiO) and one type of HfO2 gate dielectrics. Different p-type oxides and different fin structures can modulate the threshold voltage of the devices. The CuO and NiO Fin-MOS-HEMT with 60 nm fin width (W (fin)) achieves the V (th) value of 0.3 and 0.6 V, respectively. Compared with the conventional HEMT, the V (th) of NiO Fin-MOS-HEMT can be positively shifted by 2.5 V, validating the stronger 2D electron gas (2DEG) depletion by the p-type oxide and the V (th) will shift forward with the decrease of W (fin). Furthermore, the theoretical calculation model of Fin-MOS-HEMT threshold voltage is proposed, which is in good agreement with the experimental results. The proposed model can provide important guidelines for the AlGaN/GaN Fin-MOS-HEMTs development.