Impact of Diamond Passivation on fT and fmax of mm-wave N-Polar GaN HEMTs
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2022-11-10 |
| Journal | IEEE Transactions on Electron Devices |
| Authors | Xinyu Zhou, Mohamadali Malakoutian, Rohith Soman, Zhengliang Bian, Rafael Perez Martinez |
| Institutions | Stanford University |
| Citations | 12 |
Abstract
Section titled “Abstract”This article presents a modeling approach and its implementation to study the impact of the top-side diamond integration on the <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>${f}{\text {T}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>${f}{\text {max}}$ </tex-math></inline-formula> performance of a millimeter-wave (mm-wave) N-polar gallium nitride (GaN) high-electron-mobility transistor (HEMT). This approach uses a co-simulation model formed by an equivalent small-signal circuit model of the device implemented in PathWave advanced design system (ADS) and full-wave simulations of 3-D modeling diamond passivation from Ansys high frequency simulation software (HFSS). Thin-film diamond as a passivation layer and a heat spreader on top of the device channel is explored as a function of the diamond’s dielectric constant and its thickness to understand how it affects the device’s <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>${f}{\text {T}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>${f}{\text {max}}$ </tex-math></inline-formula> . The simulation results serve as a guide to the optimization of the radio frequency (RF) performance of mm-wave HEMT devices, aiding the device design of the diamond passivation. The designed methodology was applied to other passivation, such as benzocyclobutene (BCB) for benchmarking. This method allowed us to estimate the tradeoff in electrical performance for anticipated thermal benefits. A maximum reduction of 23.6% in <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>${f}{\text {T}}$ </tex-math></inline-formula> and 21.8% in <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>${f}{\text {max}}$ </tex-math></inline-formula> was obtained when the diamond passivation thickness is <inline-formula xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”> <tex-math notation=“LaTeX”>$2.7 \mu \text{m}$ </tex-math></inline-formula> with a dielectric constant of 4.