A Planar IC-Compatible Transferred Electron Device for Millimeter-Wave Operation.
Abstract
Devices with 0.5 micrometers long gates have been fabricated using E beam lithography. Since no improvement in efficiency has been obtained it is recommended to use 1-1.5 micrometers long gates which are easy to fabricate. It was also found that finger gate devices exhibit ten times smaller efficiencies (0.1%) than overlapping gate devices do. In order to produce gain at a desired frequency (lambda/2 + delta)-lines terminated by radial stubs must be connected to both gate and source. Maximum gain occurs at that frequency at which the capacitive reactances of the lines with 0<delta<lambda/4 compensate for lead and other parasitic inductances. The device breaks into oscillations when a dielectric resonator with its resonance frequency near the maximum gain frequency is placed near both drain and gate bonding pads. The oscillator frequency can be tuned over a few hundred megahertz by varying the gate voltage by approximately 10%. An unexpectedly steep (12db/octave) fall off of efficiency with frequency has been observed whose origin has not yet been identified. It is speculated that the low field region near the drain contact might cause this steep fall off. Future devices therefore will be made with reduced gate drain distance. That might perhaps enhance efficiency in general.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 23, 1988
- Accession Number
- ADA192692
Entities
People
- Hartwig W. Thim
Organizations
- Johannes Kepler University Linz