Appeal No. 2003-2130
Application 08/159,461
the gate electrode” (reply brief, page 4).
In following the method steps disclosed in col. 4 of Geipel, we find that subsequent to the
deposition of phosphorous doped polysilicon over the 150 to 800 angstroms of silicon dioxide
which provides the gate insulating layer,
the last deposited layer of polysilicon is etched to form IGFET gate electrodes.
Retaining or removing and regrowing the gate dielectric over remaining portions of
the substrate to act as an ion implantation screen in the next step is optional at this
point.
Source and drain regions are next formed by ion implantation/drive in process using
both the polysilicon and [semi-recessed dielectric oxide] areas as a mask. [Col. 4, lines
35-60; emphasis supplied.]
In comparing the methods steps of Geipel with the limitations in claim 66 that we set
forth above, it is readily apparent that it is the step of “regrowing the gate electrode over the
remaining portions of the substrate” prior to the formation of source and drain regions in Geipel
which corresponds in certain respects to the claimed “reoxidizing” step. The deficiency in this
reference disclosure with respect to the claim limitations is two fold as appellant points out.
First, there is no teaching to “regrow” the gate oxide over all of the exposed surfaces of the
patterned substrate, which includes the polysilicon layer. And, second, there is no teaching of the
thickness of the “regrown” gate oxide on the exposed substrate. With respect to the latter, the
examiner’s inherency theory is untenable because it is based on further disclosure at col. 6, lines
22-26, which involves a step in a “preferred process related specifically to the source drain
junction formation” (col. 6, lines 8-9; see also col. 4, line 60, to col. 5, line 1, and col. 6, lines
11-21; and the Office action of November 30, 2001, Paper No. 33, page 3, last three lines of the
fourth full paragraph) and not the “regrowing” step.
Accordingly, on this record, we reverse the ground of rejection under 35 U.S.C. § 103(a).
The examiner’s decision is reversed.
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