MICROWAVE DIODE RESEARCH.
Abstract
Different structures are considered for a high-voltage (harmonic generator) GaAs varactor. The performance of each design is calculated and, for comparison, also that of an epitaxial silicon varactor. All GaAs models are found to offer substantially higher quality factors than the Si model. Of the GaAs designs investigated, an abrupt junction formed on an eptiaxial layer with an exponential impurity distribution appears the most promising. Parametric amplifier diodes show noise in excess of thermal noise when driven into the forward conduction region where the gain-bandwidth product and the gain stability are enhanced. On the basis of a shot noise theory, it is shown that the excess noise is expected to increase linearly with the average forward current. Experimental measurements show that the shot noise in gallium arsenide diodes (both diffused and surface barrier) is within 50 per cent of the theoretical value. However, silicon diodes show excess noise an order of magnitude larger than that predicted by the theory. This result may be attributed to carrier storage effects which were not included in the theoretical treatment. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 20, 1964
- Accession Number
- AD0602780
Entities
People
- J. C. Irvin
- J. G. Josenhans