High-Yield Enhancement-Mode GaN p-FET With Etching-Target Layer and High-Selectivity Etching Techniques

This article presents the enhancement-mode (E-mode) GaN p-channel heterojunction field-effect transistors (p-FETs) with p-Al0.05Ga0.95N etching-target layer (ETL). The optimized high-selectivity etching technique achieves an etch rate of approximately 1 nm/min for p-GaN, while also generating a selectivity ratio of 4:1 between p-GaN and p-Al0.05Ga0.95N. High-yield E-mode p-FET with ETL has been obtained as the etching process window was expanded to 10 min. The devices achieved the characteristics of a threshold voltage ( ${V}_{\text {th}}$ ) of −1.15 V and a maximum current density ( ${I}_{{D},\max }$ ) of 6.16 mA/mm. Furthermore, the characteristics of multiple devices demonstrate the high consistency and reproducibility of p-FETs’ ${V}_{\text {th}}$ and ${I}_{\text {ON}}$ , thus providing significant opportunities for developing complementary circuit integration.