Smoothly changing voltage-variable capacitor having an extendible pn junction region

Claim 2

A voltage-variable capacitor according to claim 2 wherein said insulating layer is a silicon dioxide layer having a linearly increasing thickness with departure from the edge of said second type conductivity region, said silicon dioxide layer being further characterized by a thickness of at least 500 A., at the edge of said second type conductivity region.

Claim 3

A voltage-variable capacitor according to claim 3 wherein said silicon dioxide layer is characterized by a linear slope between 0.25 and 3.0 percent.

Claim 4

A voltage-variable capacitor according to claim 2 wherein said diminishing capacitance of said insulating layer is produced by increasing the thickness of said insulating layer in steps to produce a digitalized change in the output capacitance of said capacitor with each extension of said second type conductivity region below successively thicker steps of said insulating layer.

Claim 5

A voltage-variable capacitor according to claim 5 wherein said insulating layer increases in thickness in incremental steps having a height between 200 A., and 500 A.

Claim 6

A voltage-variable capacitor according to claim 2 wherein said semiconductive body is silicon, said insulating layer is silicon dioxide and said conductive film is a metal selected from the group consisting of molybdenum, tungsten and platinum.

Claim 7

A voltage-variable capacitor according to claim 7 further including a molybdenum heat sink bonded to said semiconductive body.

Claim 8

A voltage-variable capacitor comprising: A. a semiconductive body of first type conductivity; B. a plurality of spaced-apart regions of second type conductivity extending through a major face of said semiconductive body; C. output means connected between one said region of second type conductivity and said semiconductive body; D. a plurality of control electrodes extending between and overlying the edges of adjacent regions of second type conductivity, each of said control electrodes being insulated from the major face of said semicOnductive body by discrete insulating layers characterized by a decreasing capacitance between said control electrodes and said underlying semiconductive body with increased departure of each said insulating layer from the second type conductivity region connected to said output means; E. contact means electrically interconnecting said control electrodes; F. means for applying a control signal between said contact means and said semiconductive body to sequentially interconnect adjacent ones of said second type conductivity regions by inversion regions extending outwardly from the second type conductivity region connected to said output means, said sequential interconnection of said second type conductivity regions producing a variation in the output capacitance across said output means with increased amplitude of the control signal applied to said contact means.

Claim 9

A voltage-variable capacitor according to claim 9 wherein said insulating layers are silicon dioxide, the thickness of each said silicon dioxide layer increasing with increased departure of the insulating layers from said region of second type conductivity connected to said output means.

Claim 10

A voltage-variable capacitor according to claim 9 wherein said insulating layers are of comparable thickness and of diverse composition, said insulating layers having a dielectric constant varying inversely with the span of each said insulating layer from the second conductivity region connected to said output means.

Claim 11

A voltage-variable capacitor according to claim 9 wherein said insulating layer overlying an edge of said second conductivity region connected to said output means is a first material having a first dielectric constant and said immediately adjacent insulating layer is a laminar film consisting of a layer of said first material and an underlying layer of a second material having a dielectric constant lower than the dielectric constant of said first material.

Claim 12

A voltage-variable capacitor structure according to claim 12 wherein said first material is aluminum oxide and said second material is silicon dioxide.

Claim 13

A voltage-variable capacitor structure according to claim 9 wherein said semiconductive body is silicon, said insulating layers are silicon dioxide in thicknesses gradually increasing with increased departure of each said insulating layer from the second type conductivity region connected to said output means and said control electrodes are a metal selected from the group consisting of molybdenum, tungsten, and platinum.