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Title: Current-voltage characteristic for bipolar p-n junction devices with drift fields, including correlation between carrier lifetimes and shallow-impurity concentration

Journal Article · · J. Appl. Phys.; (United States)
DOI:https://doi.org/10.1063/1.330440· OSTI ID:6643693

We present general analytic solutions for static current-voltage characteristics of quasineutral regions of nonilluminated semiconductor bipolar devices under the following assumptions: (a) the quasineutral region has a graded shallow-level impurity concentration producing a constant built-in electric (drift) field; (b) minority carriers injected into this region stay at concentrations low enough to avoid violation of low-injection conditions; (c) the minority-carrier lifetime of this region depends on position in accordance with a power-law dependence on the shallow-level donor concentration, a dependence that is consistent with the longest minority-carrier lifetimes measured and with the physical chemistry of divacancy-donor reactions at high temperatures. The solutions presented are apparently the first that include assumption (c). Modified Bessel functions of the first and second kind appear in these solutions. From a pheonomenological standpoint, the solutions may account for defect centers associated with vacancy complexes and, in part, for the gettering observed in highly doped n-type Si. Design implications for transistors, diodes, and solar cells are discussed quantitatively for a thin drift-field Si p/n(x) junction solar cell.

Research Organization:
Department of Electrical Engineering, University of Florida, Gainesville, Florida 32611
OSTI ID:
6643693
Journal Information:
J. Appl. Phys.; (United States), Vol. 53:12
Country of Publication:
United States
Language:
English