Appeal No. 2000-0769
Application 08/997,326
We cite Banerjee et al. (Banerjee), U.S. Patent
5,665,981, issued September 9, 1997, and having an effective
filing date of October 24, 1994 (copy attached) as relevant to
the patentability of claim 8. Banerjee teaches a thin film
transistor (TFT) 20 having an active channel region 26
comprising a middle layer 32 of poly-SiGe between layers 28,
30 of poly-Si, where the channel region overlies gate 16
(col. 3, line 35 to col. 4, line 4). This bottom gate
configuration is similar to the embodiment of Appellants'
Fig. 3 and, in our opinion, it would have been obvious to
apply the bottom gate TFT teachings of Banerjee to a top gate
TFT as shown in King to provide the same advantages. Banerjee
discloses that the poly-SiGe alloy layer 32 has a lower energy
bandgap than the poly-Si and the band-edge discontinuity for
poly-SiGe is primarily in the valence band which is ideal for
confining the holes within layer 32 in the middle, away from
the high defect poly-oxide interfaces, which results in lower
leakage current and sharper sub-threshold slopes (col. 4,
lines 4-13). Thus, Banerjee expressly teaches the silicon
channel layer on a poly-SiGe layer between the poly-SiGe layer
and the gate, and the advantages thereof. Banerjee further
- 12 -
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: November 3, 2007