Plasma effects in a micromachined floating-gate high-electron-mobility transistor

TL;DR

This paper models plasma effects in a micromachined high-electron-mobility transistor with a microcantilever gate, analyzing how plasma phenomena influence mechanical and electrical responses under various biases.

Contribution

It introduces a comprehensive model combining mechanical motion and plasma effects in a micromachined HEMT, providing insights into device response characteristics.

Findings

Mechanical oscillation amplitudes peak near depletion voltages

Output signals show pronounced maxima at specific bias voltages

Frequency and damping depend on bias voltage and device parameters

Abstract

We study plasma effects in a micromachined high-electron mobility transistor (HEMT) with the microcantilever serving as the gate using the developed a model. The model accounts for mechanical motion of the microcantilever and spatio-temporal variations (plasma effects) of the two-dimensional electron gas(2DEG) system in the transistor channel. The microcantilever mechanical motion is described in the point-mass approximation. The hydrodynamic electron transport model is used to describe distributed electron plasma phenomena in the 2DEG system. Using the developed model, we calculated the response function characterizing the amplitude microcantilever oscillations and the output electric signal as functions of the signal frequency and the bias voltage for the devices with different parameters. We find the voltage dependences of the frequency of the mechanical resonance and its damping. In particular, it is demonstrated that the amplitudes of the mechanical oscillations and output electric signal exhibit pronounced maxima at the bias voltages close to the voltage of the 2DEG channel depletion followed by a steep drop with further increase in the bias voltage.