Appeal No. 2002-0575
Application No. 09/477,982
OPINION
We have carefully considered the entire record before us, and we will reverse the
obviousness rejection of claims 18 through 23.
Amano discloses a LED fabricated on a silicon carbide substrate. The examiner
acknowledges (final rejection, page 2) that “Amano does not disclose (1) growing undoped GaN
layers grown to sand witch [sic, sandwich] the GaInN active layer, (2) providing specific carrier gas
of hydrogen or nitrogen for specific set of layers.”
With the exception of a single embodiment, all of the LEDs formed in Sugiura are formed
on a sapphire substrate. The single embodiment (Figure 18) formed on a silicon carbide substrate
51 has an indium gallium nitride layer 54 sandwiched between two doped layers of gallium nitride
53 and 55. Another embodiment (Figure 3) that has an indium gallium nitride layer 16 sandwiched
between two gallium nitride layers 15 and 17 is formed on a sapphire substrate 11. This latter
embodiment is silent as to doping of the two gallium nitride layers. In other embodiments (Figures
24 through 38), the undoped gallium nitride layer in each of the embodiments is denoted by the
prefix “un.” Although we agree with the examiner (final rejection, page 3) that “Sugiura et al
teaches the suitability of using undoped GaN layers,” we do not, however, agree with the examiner
that “[i]t would have been obvious to one of ordinary skill in the art to form undoped GaN layers in
place of doped GaN layers in the invention of Amano et al to sandwich the InGaN active device
layer.” The examiner has not successfully demonstrated that Sugiura teaches interchangeability of
doped and undoped gallium nitride layers in LEDs. We likewise agree with the examiner (final
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