Frequency Conversion in Punch-Through Semiconductor Devices.
Interim technical rept.,
MICHIGAN UNIV ANN ARBOR ELECTRON PHYSICS LAB
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The objectives of this investigation are to study the frequency conversion properties of punch-through semiconductor devices and to establish the frequency regions of their potential application as efficient detectors and mixers of information-bearing signals. The physics of two punch-through devices are studied in detail the three-terminal punch-through transistor and the two-terminal BARITT barrier injection transit-time diode. The particle current injection process for both devices is examined and identified as simple diffusion over a potential barrier exponential injection with respect to the barrier height. Dc and small-signal ac models for both punch-through structure are derived from standard bipolar junction transistor theory by applying a current-dependent, rather than the standard voltage-dependent, boundary condition for the minority carrier concentration at the collector edge of the low-field base region. The small-signal models include carrier transit-time effects in the diffusion-drift, reverse-biased regions of the devices by means of a transit-time factor similar to the factor used in the standard frequency domain analysis of pure saturated drift transit-time diodes. The small-signal noise properties of the BARITT diode are developed employing the same techniques used in the formulation of the BARITT diode circuit model. Both, small-signal impedances predicted by the circuit model and small-signal noise measures predicted by the noise analysis, compare very well with experimentally measured values of typical BARITT structures.
- Electrooptical and Optoelectronic Devices
- Solid State Physics