Andrew S Robinson

US Patent:

54061636, Apr 11, 1995

Filed:

Oct 30, 1992

Appl. No.:

7/969939

Inventors:

Paul L. Carson - Ann Arbor MI
Dale W. Fitting - Golden CO
Andrew L. Robinson - Ann Arbor MI
Fred L. Terry - Saline MI

International Classification:

H01L 4108

US Classification:

310334

Abstract:

An ultrasonic sensing array having ultrasonic transducer elements formed on a micromachined single-crystal semiconductor wafer provided with a deep recess under each transducer. Etch-altering dopants are diffused into the wafer to form rimmed support structures for dielectric stress-balanced elements. Composite dielectric layers are grown on both surfaces of the wafer. One composite layer serves as a diaphragm underlying the transducer elements. The other composite layer serves as a mask for etching away the substrate under each transducer element to form the deep recess while leaving the support structures and diaphragm layer. The resulting hollow or recess under each transducer element reduces the parasitic capacitance between the transducer and support substrate. The transducer elements are made by forming conductive bottom plates on the dielectric diaphragm layer, adding a piezoelectric polymer layer and thereafter forming the conductive top plates. The resulting ultrasonic sensors are capable of operation over a wide variety of frequencies with improved sensitivity and decreased acoustic crosstalk between sensor elements, Switching transistors may also be fabricated as part of the patterned semiconductor substrate.

US Patent:

51608707, Nov 3, 1992

Filed:

Jun 25, 1990

Appl. No.:

7/543267

Inventors:

Paul L. Carson - Ann Arbor MI
Dale W. Fitting - Golden CO
Andrew L. Robinson - Ann Arbor MI
Fred L. Terry - Saline MI

International Classification:

H01L 4108

US Classification:

310339

Abstract:

An ultrasonic sensing array having ultrasonic transducer elements formed on a micromachined single-crystal semiconductor wafer provided with a deep recess under each transducer. Etch-altering dopants are diffused into the water to form rimmed support structures for dielectric stress-balanced elements. Composite dielectric layers are grown on both surfaces of the wafer. One composite layer serves as a diaphragm underlying the transducer elements. The other composite layer serves as a mask for etching away the substrate under each transducer element to form the deep recess while leaving the support structures and diaphragm layer. The resulting hollow or recess under each transducer element reduces the parasitic capacitance between the transducer and support substrate. The transducer elements are made by forming conductive bottom plates on the dielectric diaphragm layer, adding a piezoelectric polymer layer and thereafter forming the conductive top plates. The resulting ultrasonic sensors are capable of operation over a wide variety of frequencies with improved sensitivity and decreased acoustic crosstalk between sensor elements.

US Patent:

49337408, Jun 12, 1990

Filed:

Sep 9, 1988

Appl. No.:

7/243211

Inventors:

Bantval J. Baliga - Schenectady NY
Andrew L. Robinson - Ann Arbor MI

Assignee:

General Electric Company - Schenectady NY

International Classification:

H01L 2974

US Classification:

357 38

Abstract:

An improved lateral insulated gate transistor includes a dual function anode and employs specially configured anode and cathode regions within the drift layer to promote lateral current flow. A vertical diode is disposed between a substrate cathode and anode of the device. Under forward bias conditions, the device exhibits insulated gate controlled conduction, and under reverse bias conditions, the device exhibits conduction between the substrate cathode and anode of the vertical diode.