GaAs Transferred Electron Devices Research Articles

High-efficiency GaAs transferred electron device operation and circuit design

In this paper it is shown that a GaAs transferred electron device is adequately described by a simple, static IV characteristic. This characteristic is used in a time domain computer simulation with the microwave circuit represented by transmission line equivalent circuit from which the voltage and current waveforms associated with the device are derived for a particular device IV characteristic and circuit. These data are analyzed for efficiency, frequency of oscillation, and starting transient and then are observed as various device and circuit parameters are changed in the simulation. From this study and parameter scan, the criterion for an efficient GaAs oscillator circuit and the maximum dc to RF conversion efficiency for device of a given quality, as specified by its current peak to valley ratio are found. Experimental observation of waveforms and efficiency and their dependence on the circuit and device parameters were then seen to be in good agreement, thus justifying the use of the phenomenological I-V characteristic. For a device with a current peak to valley ratio of 2, the theoretical and experimentally observed conversion efficiency limit appears to be slightly less than 20 percent. The use of the simple I- V characteristic is appropriate down to frequencies less than the "transit" frequency.

On scanning electron microscope conduction-mode signals in bulk semiconductor devices: annular geometry

Beam-induced signals in the scanning electron microscope provide a means of studying the bulk of semiconductors. This paper develops a two-dimensional theory to predict the spatial distribution of the signal in annular devices and it is shown that geometry and field-dependent contrast can occur. These signals provide a means of studying crystal defects and resistivity variations. Experiments on planar geometry GaAs transferred electron devices support the theoretical predictions.

CW microwave amplification from circuit-stabilized epitaxial GaAs transferred electron devices

Stable c.w. reflection-type amplification at C- X-band frequencies has been obtained from circuit-stabilized GaAs transferred electron devices biased as high as three times threshold. An instantaneous fractional bandwidth exceeding 50% and a small-signal linear gain near 10 dB have been realized with a single device for center frequencies from 5.0 to 9.0 GHz. A -1-dB-gain compression-power output typically above 100 mW and a total saturated power output near 1 W have been measured. A narrow-band doubly tuned amplifier response with a linear gain of 40 dB has also been measured. With a noise figure of 15 dB, these amplifiers have a dynamic range in excess of 90 dB. Highly nonlinear effects have been observed for large-signal narrow-band operation. Both gain and hysteresis effects have been observed. Large-signal effects of bias, frequency, and power level on amplifier performance have been measured.

On scanning-electron-microscope conduction-mode signals in bulk semiconductor devices: linear geometry

The spatial distribution of scanning microscope conduction-mode signals in bulk specimen, with bias, is predicted by a one-dimensional theory in linear geometry devices. Micrographs of GaAs transferred-electron devices under different bias conditions confirm the theory. The evaluation of minority-carrier lifetime from such a study is also discussed.

Self-pumped parametric amplification with GaAs transferred-electron devices

The letter reports experimental results obtained with a non-degenerate-type self-pumped parametric amplifier using GaAs transferred-electron devices. Gains of as much as 30dB, noise figures as low as 18dB, and instantaneous gain-bandwidth products of about 50MHz have been obtained at Xband signal frequencies with the amplifier using GaAs transferred-electron devices oscillating at Q band frequencies.