Appeal No. 1998-1660
Application No. 08/108,499
wafer is controlled to satisfy a particular inequality
relationship.
Claim 11 is illustrative of the invention and reads as
follows:
11. A GaAs single crystal characterized in that the ratio
D/d satisfies the following inequalities in a lattice
o
constant measurement area of a wafer of said GaAs,
6 -5
4 X 10- # D/d # 4 X 10 ; and
o
16 3
that a density of contained Si atoms is at most 1 x 10 cm- ;
wherein said wafer has at least one straight-line length
extending at least 2.5 cm in bidirection from its center, said
lattice constant measurement area means an area of said wafer
on a straight-line extending at least 2.5 cm in bidirection
from the center of the wafer, D is defined as the value of
difference between the maximum and minimum values of lattice
constants measured entirely across said lattice constant
measurement area at room temperature, with a series of
individual measurements having a unit measurement area of 1 -
100 mm arranged on said straight line, the unit measurement2
area being an area on which a measurement was taken by a
measuring device; and d is defined as the lattice constant at
o
room temperature of stoichiometric composition GaAs single
crystal being the theoretical composition of GaAs single
crystal.
The Examiner relies on the following prior art:
Clarke et al. (Clarke) 4,544,417 Oct. 1,
1985
(Filed May 27, 1983)
S. M. Sze (Sze), Physics of Semiconductor Devices, 33 (Second
Edition, John Wiley & Sons, 1981).
2
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