Robust SiN<sub><italic>x</italic></sub>/AlGaN Interface in GaN HEMTs Passivated by Thick LPCVD-Grown SiN<sub><italic>x</italic></sub> Layer

Low-pressure chemical vapor deposition (LPCVD) technique is utilized for SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> passivation of AlGaN/GaN high-electron-mobility transistors (HEMTs). A robust SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> / AlGaN interface featuring high thermal stability and well-ordered crystalline structure is achieved by a processing strategy of “passivation-prior-to-ohmic” in HEMTs fabrication. Effective suppression of surface-trap-induced current collapse and lateral interface leakage current are demonstrated in the LPCVD-SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> passivated HEMTs, as compared with conventional plasma-enhanced chemical vapor deposition-SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> passivated ones. Energy dispersive X-ray spectroscopy mapping analysis of SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /AlGaN interfaces suggests the interface traps are likely to stem from amorphous oxide/oxynitride interfacial layer.