Christopher Tarr Doucette

US Patent:

51648130, Nov 17, 1992

Filed:

May 8, 1991

Appl. No.:

7/700107

Inventors:

Scott C. Blackstone - Needham MA
Philip L. Hower - Concord MA
Elizabeth M. Roughan - Newton MA
Christopher H. Doucette - Clinton MA
Roy Lee - Andover MA
Carolyn Q. Cotnam - Waltham MA

Assignee:

Unitrode Corporation - Billerica MA

International Classification:

H01L 2948
H01L 21300

US Classification:

257623

Abstract:

A new diode structure is provided by bonding two semiconductor materials together having a low capacitance, a large contact area and mechanical ruggedness. The cross-sectional area of at least one of the semiconductor materials is reduced in the region of the bond resulting in a structure with either an hourglass or truncated hourglass-like cross-section. A diode PN junction is contained in the neighborhood of the area of reduced cross section. The diode so constructed provides a sufficient spacing between the unbonded semiconductor regions to reduce total packaged diode capacitance without introducing a spacer layer. The diode is processed to limit the area of the PN junction formed therein to the region of the bonding between the semiconductor materials, without limiting the metallized contact area, further controlling the diode capacitance as well as other electrical characteristics. The outer ends of the diode parallel to the bond, comprising typically P and N type semiconductor regions, are typically connected to metal leads which comprise the diode leads and the diode is packaged to form a mechanically and electrically stable low capacitance diode. This diode can be encapsulated such that no void or cavity exists within the interior of the structure without changing the diode construction process.