MICROWAVE SOLID-STATE DEVICES.
Abstract
Consideration of first order performance criteria indicate that zero bias cut-off frequencies up to 270 Gc for graded junction varactors (lower values for step junctions), are required for optimum utilization of existing pumps for low noise performance at room temperature. It is concluded that such improvement in gallium arsenide varactors can be made utilizing the epitaxial structure, and that the present film quality is the major limitation on varactor performance. Accurate evaluation of the film characteristics is required for improving the growth process, and methods of evaluation are discussed. It is pointed out that determination of the differential capacitance of a p(+)-n junction formed on the n-type film can in principle be used to determine the net donor concentration in the film at a point determined by the junction bias and it is suggested that a measurement of the differential resistance (determined at 1 Gc) at the same bias point can be used to calculate the resistivity at the same point in the film. Thus the two measurements can be used to obtain values of the net doping and mobility in regions of the film accessible to the sweep-out effect of the biased p(+)-n junction. Some experimental data are given which suggest that excessive concentrations of deep lying recombination centers can result in poor mobility in the films. Temperature variation of capacitance also indicates the presence of such impurities. The use of transmission techniques at 1 Gc to determine the resistance and capitance of varactor diodes is discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 31, 1962
- Accession Number
- AD0615891
Entities
People
- A. E. Bakanowski
- J. C. Irvin
- J. H. Forster