Appeal No. 2005-0453 Page 2
Application No. 09/893,866
INTRODUCTION
The claimed invention relates to the production of a crystallized silicon film for use in
polycrystalline thin film transistors (TFTs) of active matrix (AM) liquid crystal displays (LCDs)
(specification, p. 1, ll. 5-10). It is known in the art that silicon films enriched with a small
amount of a trace impurity, such as nickel (Ni), can be annealed more quickly than pure silicon
films due to the catalytic action of the impurity on the crystallization process (specification, p. 1,
ll. 12-16). According to the specification, introduction of the impurity into the silicon has
conventionally been accomplished using: (1) an impurity-rich liquid coating on the silicon film;
(2) an evaporated impurity layer on the silicon film; and (3) by implanting the impurity into the
silicon film (specification, p. 1, l. 16 to p. 2, l. 5). In Appellant’s process, the impurity is
introduced during a sputtering process wherein a target material including the impurity is
sputtered onto a substrate. Because the target material includes the impurity, the sputtered layer
of silicon includes the impurity incorporated therein (specification, p. 7, ll. 18-23). Claims 1 and
12 are illustrative of the invention on appeal:
1. In the fabrication of liquid crystal displays (LCDs), a method for forming silicon films
with a controlled amount of trace impurities, the method comprising:
forming a target including silicon and a first concentration of a first impurity;
supplying a substrate; and
sputter depositing a film of silicon on the substrate including a second concentration of
the first impurity.
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Next
Last modified: November 3, 2007