Transport theory of high-frequency rectification in Schottky barriers

Abstract

A theory based on the Boltzmann equation is used to study rectification by Schottky barriers at frequencies as high as infrared. This theory is concerned only with effects originating inside the space‐charge region, the voltages across this region being regarded as given. Thus, we confine our attention to transport mechanisms and exclude what are known as ’’circuit effects.’’ Typically, it is found that rectification is nearly constant from zero frequency to the plasma frequency of the bulk semiconductor, then drops as ω⁻². A reversal of the sign of the rectification current is predicted near ω_p. The small‐signal impedance of the junction is calculated as a function of frequency. The theory is extended to mixing of two weak signals, and mixer output is calculated as a function of beat frequency. It is found that this output can be much larger than the value one would estimate from the ideal‐diode equation.