Abstract A dielectrically isolated, pressure responsive silicon diaphragm includes a single crystal substrate bonded to a single crystal strain gage component with an intermediate insulating layer and glass bonding layer. The boric oxide enriched glass has a lower softening temperature than the insulating layer and semiconductor and a matching expansion coefficient. Illustratory products are integral silicon diaphragms, integrated circuits, and power devices for high temperature applications where junction isolation is useless. In the method of fabrication the composite is bonded at elevated temperature under pressure and the temporary substrate is removed mechanically and by a final preferential etch. Active components with thinner semi-conductor layers of uniform thickness can be produced.
A DIELECTRICALLY ISOLATED INTEGRAL SILICON DIAPHRAGM COMPRISING A PRESSURE RESPONSIVE SINGLE CRYSTAL SILICON SUBSTRATE, A PATTERNED SILICON DIOXIDE LAYER HAVING AT LEAST ONE OPENING IN WHICH IS FORMED A SINGLE CRYSTAL SILICON STRAIN GAGE COMPNENT, SAID SINGLE CRYSTAL SILICON SUBSTRATE AND SAID PATTERNED SILICON DIOXIDE LAYER WITH A SINGLE CRYSTAL SILICON STRAIN GAGE COMPONENT BEING COMPLETELY DIELECTRICALLY ISOLATED AND BONDED TOGETHER WITH AT LEAST ONE OTHER INTERMEDIATE SILICON DIOXIDE INSULSTING LAYER AND ONE INTERMEDIATE GLASS BONDING LAYER, SAID GLASS BONDING LAYER CONSISTING ESSENTIALLY IN MOLE PERCENT OF 15-20 PERCENT BORIC OXIDE AND 80-85 PERCENT SILICON DIOXIDE, AND HAVING A THERMAL EXPANSION COEFFICIENT THAT APPROXIMATELY MATCHES THE THERMAL EXPANSION COEFFICIENT OF SILICON SAID SUBSTRATE BEING MADE OF N-TYPE SILICON, AND SAID GLASS BONDING LAYER HAVING A THICKNESS BETWEEN 0.5 AND 5 MICRONS
Claim 2
Dependent Claim
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A DIELECTRICALLY ISOLATED INTEGRAL SILICON DIAPHRAGM COMPRISING A PRESSURE RESPONSIVE SINGLE CRYSTAL SILICON SUBSTRATE, A PATTERNED SILICON DIOXIDE LAYER HAVING AT LEAST ONE OPENING IN WHICH IS FORMED A SINGLE CRYSTAL SILICON STRAIN GAGE COMPNENT, SAID SINGLE CRYSTAL SILICON SUBSTRATE AND SAID PATTERNED SILICON DIOXIDE LAYER WITH A SINGLE CRYSTAL SILICON STRAIN GAGE COMPONENT BEING COMPLETELY DIELECTRICALLY ISOLATED AND BONDED TOGETHER WITH AT LEAST ONE OTHER INTERMEDIATE SILICON DIOXIDE INSULSTING LAYER AND ONE INTERMEDIATE GLASS BONDING LAYER, SAID GLASS BONDING LAYER CONSISTING ESSENTIALLY IN MOLE PERCENT OF 15-20 PERCENT BORIC OXIDE AND 80-85 PERCENT SILICON DIOXIDE, AND HAVING A THERMAL EXPANSION COEFFICIENT THAT APPROXIMATELY MATCHES THE THERMAL EXPANSION COEFFICIENT OF SILICON SAID SUBSTRATE BEING MADE OF N-TYPE SILICON, AND SAID GLASS BONDING LAYER HAVING A THICKNESS BETWEEN 0.5 AND 5 MICRONS