High Performance Flip-Structure Enhancement-Mode HEMT with Face-to-Face Double Gates

Area of Science:

• Semiconductor device physics
• Advanced materials science
• Power electronics

Background:

• Conventional enhancement-mode (E-mode) high electron mobility transistors (HEMTs) often rely on etching the AlGaN layer, which can cause damage and compromise performance.
• Achieving both high threshold voltage and low on-resistance in E-mode HEMTs remains a challenge.

Purpose of the Study:

• To propose and analyze a novel double gates flip-structure enhancement-mode (E-mode) high electron mobility transistor (DFF HEMT).
• To demonstrate the advantages of a face-to-face double gate structure with a step field plate for improved device characteristics.

Main Methods:

• Device simulation and characterization of the proposed DFF HEMT.
• Comparative analysis against conventional MIS gate E-mode HEMT and MIS-FP HEMT.

Main Results:

• The DFF HEMT utilizes face-to-face double gates to restore 2DEG in the on-state, increasing saturation current and reducing on-resistance.
• The double-gate structure enables E-mode operation via work function difference, avoiding etch damage and maintaining high threshold voltage.
• The step gate field plate enhances breakdown voltage (BV), with simulated values of 0.8 V threshold voltage, 465 V BV, and 494 mA/mm drain current.
• Figure of Merit (FOM) is significantly improved, 79.8% and 444.2% higher than conventional MIS-FP HEMT and MIS HEMT, respectively.

Conclusions:

• The proposed DFF HEMT offers a promising alternative for high-performance power electronics.
• The flip-structure design minimizes leakage current and facilitates fabrication.
• This novel device architecture successfully enhances key performance metrics like breakdown voltage and on-resistance.