Method of making a getterer for multi-layer wafers
AssigneeAT&T Corp.
InventorWilliam G. Easter
Life of this patent
Estimating the term…
Abstract
A method of making a gettering structure for dielectrically isolated wafer structures, such as bonded wafers. A getterer layer is deposited over the wafer having semiconductor regions isolated from each other by trenches. The polysilicon is etched back leaving the polysilicon on the sides of the regions. The polysilicon may be doped. The polysilicon is oxidized and a second layer of polysilicon may be deposited to fill voids in the trenches.
Claims13
A method of making a wafer, the wafer having a working layer and a handle layer, CHARACTERIZED BY THE STEPS OF:
- trenching the working layer to form portions thereof having minor surfaces;
- depositing polysilicon over the working layer and in the trenches to cover the minor surfaces;
- and
- etching the polysilicon back to retain the polysilicon on the minor surfaces;
- wherein the polysilicon on the minor surfaces is a gettering layer.
A method of making a wafer, the wafer having a working layer and a handle layer separated from the working layer by an insulating layer, CHARACTERIZED BY THE STEPS OF:
- trenching the working layer to form portions thereof having minor surfaces, the trench extending to the insulating layer;
- depositing a polysilicon gettering layer on at least one of the minor surfaces;
- etching the polysilicon back to retain the polysilicon on the minor surfaces;
- forming an oxide on at least the polysilicon gettering layer;
- depositing polysilicon over the working layer to ensure the filling of the trenching and
- etching back the polysilicon to leave the polysilicon in the trenches.
Dependencies are inferred from the claim text.