This paper reports on the analytical approach for designing field plates for reducing the electric field in the channel and at the surface of heterostructure field-effect transistors (HFETs) for a given drain voltage, with the smallest possible increase of the gate capacitance. The analytical calculations for GaN-based HFETs are in good agreement with the two-dimensional numerical simulations. © 2005 IEEE.

Shreepad Karmalkar

Department of Electrical Engineering

Capacitance

Computer simulation

Electric fields

Electric insulators

Gallium nitride

Gates (transistor)

Heterojunctions

Mathematical models

Analytical modeling

FIELD-PLATE ENGINEERING

Gate capacitance

HETEROSTRUCTURE FIELD-EFFECT TRANSISTORS (HFETS)

Field effect transistors

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Field-plate engineering for HFETs

IEEE Transactions on Electron Devices

We investigate the breakdown (V br) enhancement potential of the field plate (FP) technique in the context of AlGaN/GaN power HEMTs. A comprehensive account of the critical geometrical and material variables controlling the field distribution under the FP is provided. A systematic procedure is given for designing a FP device, using two-dimensional (2-D) simulation, to obtain the maximum V br with minimum degradation in on-resistance and frequency response. It is found that significantly higher V br can be achieved by raising the dielectric constant (ε i) of the insulator beneath the FP. Simulation gave the following estimates. The FP can improve the V br by a factor of 2.8-5.1, depending on the 2-DEG concentration (n s) and ε i. For n s = 1 × 10 13/cm 2, the V br can be raised from 123 V to 630 V, using a 2.2 μm FP on a 0.8 μm silicon nitride, and 4.7 μm gate-drain separation. The methodology of this paper can be extended to the design of FP structures in other lateral FETs, such as MESFETs and LD-MOSFETs.

Enhancement of breakdown voltage in AlGaN/GaN high electron mobility transistors using a field plate

We investigate a technique that has the potential to enhance the breakdown voltage (Vbr) of AlGaN/GaN high electron mobility transistors (HEMTs) beyond 1 kV. The technique involves incorporation of a field plate (FP) connected to the gate and placed over a stepped insulator (SI). A comprehensive account of the critical geometrical and material variables controlling the field distribution under the FP is provided. A systematic procedure is given for designing a SIFP device, using 2-D simulation, to obtain the maximum Vbr with minimum degradation in on-resistance and frequency response. Simulations show that, for a 2-DEG concentration of 1 × 1013cm-2, the maximum Vbr achievable with a stepped aluminum nitride (silicon nitride) insulator can be 2.6 (2.3) times higher than that with a uniform insulator; Vbr∼1 kV can be obtained using a gate to drain separation as low as ∼7 μm. The methodology of this paper can be extended to t he design of SIFP structures in other lateral FETs, such as MESFETs and LD-MOSFETs.© 2001 Elsevier Science Ltd. All rights reserved.

Solid-State Electronics

Very high voltage AlGaN/GaN high electron mobility transistors using a field plate deposited on a stepped insulator

IEEE Electron Device Letters

High Breakdown Voltage AlGaN–GaN HEMTs Achieved by Multiple Field Plates

30-W/mm GaN HEMTs by Field Plate Optimization

A GaAs-based field-modulating plate HFET with improved WCDMA peak-output-power characteristics

Journal	IEEE Transactions on Electron Devices
ISSN	00189383
Open Access	No