Ultrasonic image sensing array with acoustical backing
US5406163A · kind A · utility
Inventors
Key dates
| Filing date | Oct 30, 1992 |
| Grant date | Apr 11, 1995 |
| Priority date | — |
| Expiry date | Oct 30, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S310/80
- WIPO fieldChemical engineering
- WIPO sectorChemistry
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…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.