Electrical and Computer Engineering ETDs

Publication Date

Spring 3-15-1971


Scattering parameters are developed for diodes and tran­sistors. The parameters are developed through a modification of the wave equation from quantum mechanics. The effects of pulsed X-ray radiation on these devices is then calculated with the use of these parameters.

Various methods of analyzing semiconductor junction de­vices are discussed. These methods include diffusion theory, invariant imbedding and quantum mechanics. The background in these areas necessary for a discussion of semiconductor models is outlined.

Models resulting from the three basic approaches are presented. These include the Ebers-Moll Model, the Charge Control Model, the Linville Model, the Gore Model, the MLB (McKelvey, Longini and Brody) Model. The importance of using the correct model in calculating the effects of ionizing radiation is emphasized.

Small-signal models are introduced. Typical parameters such as z or h-parameters are discussed in relation to the use of scattering coefficients (s-parameters). An extension of small-signal parameters to a large signal model is included. It is then shown that semiconductors can be modeled through quantum mechanics by introducing a new term into the Schrodinger Wave Equation. This term successfully accounts for the minor­ity carrier lifetime in semiconductors. Thus, junction devices can be correctly analyzed when the potential energy distribu­tion and the minority carrier lifetime of the unit are known.

In order to analyze nonlinear potential functions the WKB (Wentzel-Kramers-Brillouin) Approximation is used. This approximation is developed on the basis that it is valid until the breakdown field of the semiconductor is approached.

Results obtained by the above method are equivalent to the results obtained from diffusion theory in the regions of normal operation. The new method can be used for transistors operating in cut-off or saturation as well as the usual region of operation.

Finally, the s-parameters are measured for a set of common­base transistors. The results of these measurements are then applied to the calculation of the expected response of these devices to ionizing radiation.

Document Type




Level of Degree


Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Lewellyn Boatwright

Second Committee Member

W. J. Byatt

Third Committee Member

Harold Dean Southward

Fourth Committee Member

Wayne Willis Grannemann