Determination of the Basic Device Parameters of a GaAs MESFET

Abstract

This paper describes a new technique to determine the basic properties of the active channel of a gallium arsenide (GaAs) metal‐semiconductor field effect transistor (mesfet). The effective gate length, channel thickness, and carrier concentration are determined from dc parameters. A precise method of measuring the dc parameters is also given. The new techniques are demonstrated using a wide variety of sample devices. It is also shown that microwave performance parameters, such as the maximum output power and minimum noise figure, are well predicted by dc parameters. Calculated values of the intrinsic and extrinsic dc parameters, using simple analytical expressions developed in terms of the geometrical and material parameters of a device, are shown to be in excellent agreement with their measured values. These expressions can be used as a basis for device design.

High‐efficiency class‐C power‐amplifier module

“…Second, the charge-storage effects in the small-signal elements are illustrated by three nonlinear parameters, such as the gate-source capacitance C gs , the gate-drain capacitance C gd , and the drain-source capacitance C ds . The gate, source, and drain parasitic resistances can be obtained by extraction through a set of S parameters of a LDMOS biased at V GS ϭ V DS ϭ 0 V [4].…”

“…2), and the solution is given by the (ideally) common intersection of the three circles derived from the measured data [1]. There are different methods to implement the six-port reflectometer, such as using two directional couplers and two voltage probes [2], and using three-coupled lines (coaxial lines, stripline, waveguide, or microstrip lines) [3,4]. Another way is by using a five-port junction (ring or disc) and a directional coupler [5].…”

Novel technique for estimating metal semiconductor field effect transitor parasitics

“…As a result of knowing these bias-independent parameters, optimization-based processes for extracting small-signal model parameters turn out to be more accurate, more reliable, and faster [2]. Unlike other techniques (e.g., [3]), which predict the DC value of R g , our technique extracts its RF value, which is consistent with microwave applications. Moreover, in contrast to other techniques (e.g., [4]), our method allows the extraction of the pad capacitances without a need for building up special test structures on the substrate.…”

Interfacial gate resistance in Schottky-barrier-gate field-effect transistors

“…The gate metallization resistance clearly contributes to R g [1,2]. It does so in a distributed way, which reduces the effect to a third of the end-to-end gate finger resistance: (1) To distinguish this well-known resistance from the additional component which is the topic of this paper, we have introduced the subscript a to indicate access resistance along the gate finger.…”