Electronic Decisions Incorporated

Martin J Brophy

Michael J Hoskins

Steven S Mahon

A process for fabricating an acoustic charge transport (ACT) integrated circuit, comprises the steps of providing a semi-insulating wafer; providing an epitaxial layer with a thickness and carrier concentration appropriate for an ACT device on the semi-insulating wafer; providing at least one circuit element semiconductor layer on the surface of the epitaxial layer for construction of an integrated circuit element, the at least one semiconductor layer having a thickness substantially less than the thickness of the ACT epitaxial layer and having a carrier concentration substantially greater than the ACT epitaxial layer; removing lateral conductivity of the entire ACT epitaxial layer except in the regions associated with the at least one circuit element semiconductor layer and the ACT device in order to achieve lateral electrical isolation between the circuit element semiconductor layer and the ACT device; providing ohmic contacts on the at least one layer and on the ACT device; providing a first metal layer on selected areas on the at least one layer and the ACT device; rendering semi-insulating the epitaxial layer underneath the at least one layer to provide significant vertical electrical isolation with minimal detrimental effect on the electrical characteristics of the circuit element to be constructed on the semiconductor layer; and providing at least one layer of dielectric material on the wafer; and providing at least a second metal layer connected at selected areas to the first metal layer.

Acoustic charge transport integrated circuit process

A method for electrically isolating an integrated circuit element in an acoustic charge transport device comprises the steps of providing a semi-insulating substrate; providing an epitaxial layer with a thickness and carrier concentration appropriate for an ACT device; providing a circuit element semiconductor layer in the epitaxial layer for construction of an integrated circuit element, the layer having a thickness substantially less than the thickness of the epitaxial layer and having a carrier concentration substantially greater than the ACT epitaxial layer; laterally isolating the semiconductor layer from other regions of the ACT epitaxial layer; and bombarding the semiconductor layer with protons at a dose sufficient to provide significant vertical electrical isolation from underlying regions of the epitaxial layer semi-insulating with minimal detrimental effect on the electrical characteristics of the semiconductor layer.

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Urbana, IL, United States of America

Martin J Brophy