Influence of the AlGaN barrier thickness on polarization Coulomb field scattering in an AlGaN/AlN/GaN heterostructure field-effect transistor

Abstract

In this study rectangular AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) with 22-nm and 12-nm AlGaN barrier layers are fabricated, respectively. Using the measured capacitance–voltage and current–voltage characteristics of the prepared devices with different Schottky areas, it is found that after processing the device, the polarization Coulomb field (PCF) scattering is induced and has an important influence on the two-dimensional electron gas electron mobility. Moreover, the influence of PCF scattering on the electron mobility is enhanced by reducing the AlGaN barrier thickness. This leads to the quite different variation of the electron mobility with gate bias when compared with the AlGaN barrier thickness. This mainly happens because the thinner AlGaN barrier layer suffers from a much stronger electrical field when applying a gate bias, which gives rise to a stronger converse piezoelectric effect.

Performance analysis of GaN-based high-electron-mobility transistors with postpassivation plasma treatment*

“…The virtual gate will result in the reduction of 2DEG density, since the 2DEG density is dependent on the Schottky gate area. [19,20] With the postpassivation plasma treatment, the surface traps are effectively suppressed and thus the virtual gate effect is minimized. Consequently, the 2DEG density increases, which is consistent with the increase of drain current (see Fig.…”

X-band inverse class-F GaN internally-matched power amplifier

“…GaN high electron mobility transistors (HEMTs) have advantages in breakdown voltage, power density, and high electron, so they are good choices for high-frequency highefficiency power amplifiers. [1][2][3] Smaller in size compared with a hybrid microwave integrated circuit (HMIC) and better in thermal performance compared with a monolithic microwave integrated circuit (MMIC), the internally-matched power amplifier is a competitor for C-band and X-band applications. Class-F and inverse class-F [4] are two important ways to improve power added efficiency (PAE) in design.…”