US 3,940,783 AGranted

Majority carriers-variable threshold rectifier and/or voltage reference semiconductor structure

AssigneeSignetics Corporation

InventorBohumil Polata

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Abstract

A majority charge carrier semiconductor structure including a relatively heavily doped n type support layer, a second n type layer formed on the support layer and having a relatively light doping, a p layer formed on the second n layer, and a third n type layer having a relatively heavy doping formed atop the p layer. When voltage means is applied between top and support layers principal current flow is by majority charge carriers in either direction determined by the polarity of a pre-determined voltage. Current flow occurs substantially below the critical electric field, and free of avalanche multiplication or tunneling. In alternate embodiments the doping impurity concentration may be varied to alternately provide a device wherein the magnitude of voltage reference which determines current flow in one direction or in the opposite direction may be symmetrical, asymmetrical or highly asymmetrical.

A rectifier and reference structure utilizing majority charge carriers comprising:

a one-conductivity support layer and means for making electrical contact to said support layer, a second one-conductivity layer having a concentration differing from and carried by the support layer, an opposite-conductivity layer carried by the second layer to form a first junction, a third one-conductivity layer carried atop the opposite-conductivity layer to form a second junction and means for making electrical contact to said third layer, said opposite-conductivity layer having a decreasing impurity concentration from said second junction to said first junction wherein the second one-conductivity, opposite-conductivity, and third one-conductivity layer impurity concentrations and the opposite-conductivity layer thickness are selected to form a first depletion region at said first junction, so that when voltage means of one polarity is applied between said contacts said structure opposes current flow until a voltage magnitude is reached which causes said first depletion region to extend through the predetermined thickness of the opposite conductivity layer to intercouple said second and third one-conductivity layers, said impurity concentrations being further selected to provide said first depletion region intercoupling before avalanche and Zener breakdown of said first junction, and wherein said one-conductivity, opposite-conductivity and third one-conductivity layers have impurity concentrations further selected to form a second depletion region at said second junction, so that when voltage means of opposite polarity is applied between said contacts said structure opposes current flow until a voltage magnitude is reached which causes said second depletion region to extend through said predetermined thickness of the opposite-conductivity layer to intercouple said second and third one-conductivity layers, said impurity concentrations being further selected to provide said second depletion region intercoupling before avalanche and Zener breakdown of said second junction.

Abstract

Claims6