Abstract
A two-dimensional analysis of off-state breakdown characteristics in AlGaN/GaN HEMTs is performed by considering a deep donor and a deep acceptor in a buffer layer, with the relative permittivity of passivation layer ε<inf>r</inf> as a parameter. The analysis is made with and without impact ionization of carriers to study how the buffer leakage current affects the breakdown performance. It is shown that when ε<inf>r</inf> is low, the breakdown voltage is determined by the impact ionization of carriers, and when ε<inf>r</inf> becomes high, it is determined by the buffer leakage current. This buffer leakage current decreases as ε<inf>r</inf> increases because the electric field at the drain edge of the gate is weakened, and hence the breakdown voltage increases as ε<inf>r</inf> increases. It is also shown that when the gate voltage is more negative, the breakdown voltage in the high ε<inf>r</inf> region becomes higher because the buffer leakage current becomes smaller.
Original language | English |
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Pages (from-to) | 96-99 |
Number of pages | 4 |
Journal | Microelectronic Engineering |
Volume | 147 |
DOIs | |
Publication status | Published - 2015 Nov 1 |
Keywords
- Breakdown voltage
- Buffer leakage current
- GaN HEMT
- High-k passivation layer
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics