Investigation of SiN _x and AlN Passivation for AlGaN/GaN High-Electron-Mobility Transistors: Role of Interface Traps and Polarization Charges

Abstract

This work was supported by the Hong Kong Innovation and Technology Fund under Grant ITS/412/17FP.

Reduced Reverse Gate Leakage Current for p‐GaN Gate High‐Electron‐Mobility Transistors by a Surface‐Etching Method

“…The different slopes correlate well with different www.advancedsciencenews.com www.pss-a.com interface conditions, which is believed to be the origin of increased gate leakage. [9,20] To further explain why the direct passivation increased the leakage current, surface properties that underwent different treatments were surveyed by atomic force microscopy (AFM). Figure 4 shows the surface morphologies (5 Â 5 μm 2 ) of p-GaN surface after different processes.…”

“…The different slopes correlate well with different interface conditions, which is believed to be the origin of increased gate leakage. [ 9,20 ]…”

“…Appropriate passivation could alleviate the current collapse by reducing the surface state density and it has become one of the most crucial processes in the fabrication of HEMTs. [6,7] Although silicon nitride (SiN x ) deposited by plasma-enhanced chemical vapor deposition (PECVD) has been commonly used as a surface passivation layer for GaN, [8,9] this process introduces a significant increase in gate leakage current. [10] This causes inacceptable power loss and it is detrimental for transistors operating at a high operating voltage and power.…”

The role of SiN/GaN cap interface charge and GaN cap layer to achieve enhancement mode GaN MIS-HEMT operation

“…The SiN x passivation layer contains shallow donor-like traps with energy levels in the range of E C − E T 0.30 eV [24] (referred to also as the border traps) in SiN-passivated AlGaN/GaN HEMTs. These interface traps can be unoccupied or occupied [25] and thus behave at the interface either as a positive charge when the donor traps are unoccupied or be neutral when the traps are occupied.…”

Dynamic Ron Effect in GaN HEMT in a Zero-Voltage-Switching Circuit Due to Off-Resonance Operation

“…8 shows that as the frequency increases above 300 kHz, the red curve rises rapidly, while the black curve remains almost unchanged. Therefore, the higher the operating frequency, the greater the influence of reverse conduction on the dynamic Ron [15].…”