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US 2003/0197209 A1Published application
CCD wafers with titanium refractory metal
AssigneeDALSA Semiconductor Inc.
InventorsRobert Groulx, Raymond Frost, Yves Tremblay
Life of this patent
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Abstract
In order to make a charge couple device including an interconnect layer to contact active areas, a first layer of a first titanium nitride layer on the active areas, and then a series of alternating titanium and titanium nitride layers are deposited to form a composite sandwich structure. This structure is less prone flaking while able to withstand high temperature treatment during fabrication of backside illuminated sensors to improve quantum efficiency and reduce dark current.
Claims8
A method of making an optical sensor device subject to a high temperature anneal, comprising the steps of:
- a) providing a structure including transistors with active areas including a polysilicon gate contact layer;
- and
- b) forming an interconnect layer on said active areas by:
- (i) depositing a first titanium nitride sublayer on said active areas including said polysilicon gate contact layer;
- (ii) depositing on said first titanium nitride sublayer a plurality of alternating titanium and titanium nitride sublayers by in a collimated sputtering chamber alternately in the absence and presence of nitrogen to form a composite sandwich structure such that compressive and tensile stresses in said alternating layers substantially cancel out;
- and
- wherein said titanium nitride layers are deposited as stoichiometric layers.
4 more elements
Dependencies are inferred from the claim text.