Graduation Year

2009

Document Type

Thesis

Degree

M.S.E.E.

Degree Granting Department

Electrical Engineering

Major Professor

Lawrence P. Dunleavy, Ph.D.

Co-Major Professor

Charles Passant Baylis II, Ph.D.

Keywords

Radio Frequency, Large-signal, Self-heating, Duty cycle, Time constant

Abstract

A novel method is shown for fitting and/or validating electro-thermal models using pulsed I(V) measurements and pulsed I(V) simulations demonstrated using modifications of an available non-linear model for an LDMOS (Laterally Diffused Metal Oxide Semiconductor) device. After extracting the thermal time constant, good agreement is achieved between measured and simulated pulsed I(V) results under a wide range of different pulse conditions including DC, very short (<0.1%) duty cycles, and varied pulse widths between these extremes. A pulsed RF load-pull test bench was also assembled and demonstrated for a VDMOS (Vertically Diffused Metal Oxide Semiconductor) and an LDMOS power transistor. The basic technique should also be useful for GaAs and GaN transistors with suitable consideration for the complexity added by trapping mechanisms present in those types of transistors.

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