Appeal No. 1997-4033
Application No. 08/589,584
region 122 result in the formation of a thinner MQW
structure in the exposed spaces 202 of active region
122; whereas the relatively narrower mask stripes
201 in passive regions 121 and 123 result in the
formation of relatively thicker MQW structure in the
spaces 202 of passive regions 121 and 123.
Appellant’s specification as filed has very little to say
about the thickness of the MQW structure. It simply states 3
(at 16, lines 7-8) that "[t]he thickness of the quantum well
is proportional to the width of the mask pattern 201," which
suggests direct rather than inverse proportionality.
Moreover, a directly proportional relationship is described
in the Sasaki et al. reference (Sasaki), which explains that
[s]electively grown layer thickness depends on mask
pattern, because, under certain growth conditions, most
of the source species over the masked region do not
deposit on the mask region and they diffuse laterally to
the growth region. Layer thickness increases with the
mask stripe width. [Emphasis added.] [Sasaki at 374, 2d
col., lines 9-15.]
Consistent with this statement, Sasaki discloses using mask
stripe widths of 3 Fm and 10 Fm to form well thicknesses of
5.2 nm and 6.6 nm, respectively (Sasaki at 375, 1st col.,
3However, the specification as amended at page 11,
line 3, calls for the MQW structure to be thicker in the
passive regions than it is in the active region. See
Preliminary Amendment filed January 22, 1996 (paper No. 13).
4
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