Robust SiN_{<italic>x</italic>}/AlGaN Interface in GaN HEMTs Passivated by Thick LPCVD-Grown SiN_{<italic>x</italic>} Layer

Abstract

Low-pressure chemical vapor deposition (LPCVD) technique is utilized for SiN x passivation of AlGaN/GaN high-electron-mobility transistors (HEMTs). A robust SiN x / 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 x passivated HEMTs, as compared with conventional plasma-enhanced chemical vapor deposition-SiN x passivated ones. Energy dispersive X-ray spectroscopy mapping analysis of SiN x /AlGaN interfaces suggests the interface traps are likely to stem from amorphous oxide/oxynitride interfacial layer. Index Terms-AlGaN/GaN high-electron-mobility transistors (HEMTs), current collapse, low-pressure chemical vapor deposition (LPCVD), oxidation, SiN x passivation.

Compatibility of AlN/SiNxPassivation With LPCVD-SiNxGate Dielectric in GaN-Based MIS-HEMT

“…780°C) and suppressed oxygen contamination. However, as a passivation layer [4], [5], the effectiveness of LPCVD-SiN x to suppress current collapse has only been confirmed at low drain bias smaller than 100 V [6].…”

Device physics towards high performance GaN-based power electronics

“…基于该复合钝化结构, 在Si基GaN同时研制 出600 V耗尽型和增强型GaN功率电子器件 [30,31] , 同时 [24] . 器件单次从关态到开态的转换时间为70 ms, 且在关态下漏压从0 V扫描至200 V的 时间为46 s 裂纹 [32] . (1) 基于栅槽刻蚀(Gate Recess)技术的MIS-HEMT 或Hybrid MOS-HEMT结构 [6,8] .…”

“…HEMTs的电流坍塌特性. 在瞬态偏置点 (VGS=-5 V, VDS=50 V)的脉冲I-V测试条件下, 电流坍 塌 从 PECVD 样 品 的 16.3% 降 为 LPCVD 的 5.5%, 说 明 LPCVD-SiNx/AlGaN界面态要低于PECVD样品, 其中 一个主要的可能原因是界面氧化[32] .…”

Effect of alloying temperature on the capacitance–voltage and current–voltage characteristics of low‐pressure chemical vapor deposition SiNx/n‐GaN MIS structures

“…Low‐pressure chemical vapor deposition (LPCVD) grown‐SiN x utilized for the passivation layer and gate dielectric layer has attracted particular attention in GaN MISHEMTs . The LPCVD‐SiN x deposited at the high temperature (>600 °C) features a more compact structure, higher breakdown electric field , and larger band gap (5.3 eV, typically) , compared with the conventional plasma‐enhanced chemical vapor deposition (PECVD) grown‐SiN x .…”

“…The LPCVD‐SiN x deposited at the high temperature (>600 °C) features a more compact structure, higher breakdown electric field , and larger band gap (5.3 eV, typically) , compared with the conventional plasma‐enhanced chemical vapor deposition (PECVD) grown‐SiN x . The robust LPCVD‐SiN x /(Al)GaN interface featuring high thermal stability and well‐ordered crystalline structure can be achieved . However, due to no permission of metal into the LPCVD furnace to avoid potential contaminations, the “passivation‐prior‐to‐ohmic” process is required, which necessitates the tolerance of LPCVD‐SiN x for high ohmic alloying temperature (>800 °C).…”