Vertical current flow semiconductor device utilizing wafer bonding
AssigneeMotorola, Inc.
InventorsRobert E. Rutter, Frank S. d'Aragona
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Abstract
An intermediate contact layer (16) is created within a vertical current flow semiconductor device such as an enhanced insulated gate bipolar transistor (EIGBT) (17). An active wafer (11) that is used for forming active elements of the device is wafer bonded to a conductor (16) that is on a surface of a substrate wafer (12). The wafer bonding not only forms the intermediate contact layer (16) but also diffuses a series of P (18) and N (19) regions into the active wafer (11) thereby forming ohmic contacts between the P (18) and N (19) regions and the intermediate contact layer (16). The substrate wafer (12) provides support for the active wafer (11) during subsequent wafer processing operations.
Claims12
A method of manufacturing an enhanced insulated gate bipolar transistor (EIGBT) comprising:
- providing an active wafer that is a lightly doped semiconductor wafer of a first conductivity type having a first surface and a second surface;
- pre-depositing dopant of a second conductivity type in predetermined regions on the first surface of the active wafer;
- providing a substrate that is a highly doped semiconductor wafer of the first conductivity type having a first surface and a second surface;
- depositing a wafer bonding adhesive layer onto a first surface of the substrate;
- attaching the first surface of the active wafer to the wafer bonding adhesive layer by using a wafer bonding procedure that facilitates diffusing the pre-deposited dopant a predetermined distance into the active wafer;
- thinning the active wafer by removing a predetermined amount from the second surface of the active wafer;
- forming source and channel areas of a field effect transistor in the second surface of the active wafer;
- and
- depositing a drain electrode onto a second surface of the substrate.
A method of forming a vertical current flow semiconductor device that has a minority carrier injection diode comprising:
- providing an active wafer of a first conductivity type having a first surface and a plurality of predeposited dopant regions on a second surface of the active wafer;
- providing a substrate having a wafer bonding adhesive layer on a first surface of the substrate;
- forming an intermediate contact layer by wafer bonding the adhesive layer to the second surface of the active wafer wherein the wafer bonding facilitates forming the minority carrier injector diodes by diffusing the predeposited dopants into the second surface of the active wafer;
- and
- forming an ohmic contact to the second surface of the substrate.
Dependencies are inferred from the claim text.