Ruchika Aggarwal

Investigation of temperature dependent microwave performance of AlGaN/GaN MISHFETs for high power wireless applications

The objective of this paper is to investigate and explore the potential of AlGaN/GaN based metal insulator semiconductor heterostructure field effect transistor (MISHFET) device for high temperature applications. A temperature dependent analytical model is proposed taking into account the effect of various temperature dependent material properties. The electrical characteristics like drain current, transconductance, cut-off frequency and saturation output power are evaluated for temperature range up to 573 K and a relative comparison is done with conventional HFET structures.

AlGaN/GaN MISHFET: A novel alternative to power HFETs for high temperature microwave digital and switching applications

We report high temperature microwave characteristics of AlGaN/GaN MISHFET and present comparative studies of this device with regular HFET structures. The effect of various temperature dependent material parameters are taken into account to evaluate the small signal parameters for wide temperature (25degC < T < 300degC) range. The effect of piezoelectric and spontaneous polarization has also been considered. Our AlGaN/GaN MISHFET structure demonstrates larger drain currents, cut-off frequency and better saturation characteristics at high temperatures. Microwave saturation output power for MISHFET is obtained as 3.8 W/mm relative to 1.4 W/mm for HFET at 300degC.

Influence of physical parameters and piezoelectric polarization on charge control characteristics of Si 3 N 4 /AlGaN/GaN M̲etal I̲nsulator S̲emiconductor H̲eterostructure F̲ield E̲ffect T̲ransistor (MISHFET)

An accurate non linear charge-control model of the two dimensional electron gas (2-DEG) of an insulated gate AlGaN/GaN HFET is proposed which incorporates the dominant effect of polarization induced charge at the AlGaN/GaN interface. It is based on new polynomial dependence of sheet carrier density on position of quasi Fermi level to consider the quantum effects and to validate it from sub threshold region to high conduction region. The model gives an accurate description of the device operation for a wide range of physical parameters. The results obtained agree well with the published data.

An Analytical Drain Current Model for AlGaN/GaN Metal Insulator Semiconductor Heterostructure Field Effect Transistor (MISHFET): A Comparative Study with Conventional HFETs for High Power Microwave Applications

An analytical drain current model of a novel device architecture- AlGaN/GaN Metal Insulator Semiconductor Heterostructure Field Effect Transistor (MISHFET) has been presented to assess the microwave performance of the device for sub micron gate lengths. The model has a broad utility as it is equally applicable to HFETs as well. Both the structures have been extensively studied and a comparison is made between them. The proposed model is capable of modeling electrical characteristics like sheet carrier density, threshold voltage, drain current, cut-off frequency, etc. The MISHFET shows a considerable 36% increase in drain saturation current. The results obtained are compared with experimental data & show excellent agreement.