Investigation of a New Concept in Semiconductor Microwave Oscillators
Abstract
We have investigated a new type of millimeter wave oscillator device based on a resistive gate MESFET structure. The resistive gate establishes a uniform electric field in the regime of negative differential mobility for electrons in GaAs. At these fields, dipolar charge domains form in the channel and drift into the drain, producing microwave oscillations in the drain current. In the contiguous domain mode, a continuous sequence of charge domains forms throughout the channel. This mode is possible because the resistive gate screens the self-induced fields of each dipolar domain, keeping the field outside the domain unperturbed. Frequencies up to 100+ Ghz are preducted, independent of channel length, and the frequency should be tunable over at least one octave by varying the gate-to-source voltage. This mode has not yet been observed experimentally, since the gate resistivity on our prototype devices has been too large. These devices are presently operating a single domain transit time mode, producing oscillations in the 6 to 28 GHz range for channel lengths from 5 to 20 micron. Work is continuing to reduce the gate resistivity so that the contiguous domain mode can be observed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 30, 1990
- Accession Number
- ADA226785
Entities
People
- James A. Cooper Jr.
Organizations
- Purdue University