Gate Series Resistance Research Articles

The dV / dt capability of field-controlled thyristors

A detailed analysis of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dV/dt</tex> capability of field-controlled thyristors is presented. It is demonstrated for the first time that <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dV/dt</tex> induced turn-on can occur in these devices due to gate debiasing as a result of capacitive gate current flow if a large series gate resistance is present in the circuit. A theoretical analysis of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dV/dt</tex> capability is presented based upon this mechanism which predicts that the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dV/dt</tex> capability will decrease inversely with increasing gate series resistance at low values and become independent of the gate series resistance at very high values. The quantitative calculations of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dV/dt</tex> capability that have been made by using this theory are in very good agreement with measurements taken on asymmetrical field-controlled thyristors fabricated from wafers of various thickness. The results obtained in this study allow the conclusion that the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dV/dt</tex> capability of field-controlled thyristors are superior to that of conventional thyristors.

New method for determining the series resistances in a MESFET or TEGFET

The forward characteristic of the Schottky gate is generally used in a MESFET (or TEGFET) to measure the source or gate series resistances. An original model describing the FET behaviour when a high current flows through the gate is presented. From this model we deduce simple methods for determination of parasitic resistances.

Performance of a microwave amplitude limiter using GaAs MESFET

AbstractThis paper explains the input/output power and AM‐PM conversion characteristics of an amplitude limiter using GaAs MESFET. It is also pointed out that the AM‐PM conversion can be minimized conveniently by adding inductance in parallel to the gate terminal. In this paper the FET equivalent circuit is used for a calculation from which the relationship between the AM‐PM conversion and the gate series resistance, driving source impedance and the added inductance is clarified; the design method for minimizing AM‐PM conversion is established. The measured charactersitics are found to be the same as predicted by theory, and the correctness of the analysis is confirmed.

High-frequency high-power static induction transistor

The principal operating mechanism of the static induction transistor (SIT) that shows exponential rather than the saturated I-V characteristics, is based on the static induction of both gate and drain voltages. It is known that the SIT has low noise, low distortion, and high audio-frequency power capability. The SIT is also a very promising device for high-frequency and high-power operation because of its short channel length, low gate series resistance, small gate-source capacitance, and small thermal resistance. Si SIT's which generate a 40-W output power at 200 MHz and 10 W at 1 GHz, with a cutoff frequency higher than 2.5 GHz, have been fabricated. This is the first step toward the realization of a power microwave SIT. Future developments of a higher power higher frequency SIT can be realized by employing a distributed electrode structure and traveling-wave operation.