Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
61 words
A capacitor comprising; a first electrode formed from a metal that is easily
oxidised; a ferroelectric film formed substantially over the first
electrode; a second electrode formed on ferroelectric film; and wherein multiple crystal grain layers are constituted
by assembling crystal grains by means of grain boundaries along
a surface of the first electrode such that said ferroelectric
film is formed.
Claim 2
Dependent Claim
57 words
The capacitor as claimed in Claim 1, wherein grain
boundaries extending substantially from the first electrode to
the second electrode in each of the multiple crystal grain
layers occur at different positions between the multiple crystal
grain layers such that grain boundaries between the multiple
crystal grain layers exist continuously along the surface of the
first electrode.
Claim 3
Dependent Claim
30 words
The capacitor as claimed in Claim 1 or Claim 2, wherein the
first and second electrodes are formed from iridium and the
ferroelectric film is formed from lead zirconate titanate.
Claim 4
Dependent Claim
17 words
A memory device comprising one or more capacitors as
claimed in any of Claims 1 to 3.
Claim 5
Independent Claim
66 words
A method for manufacturing a capacitor comprising; forming a first electrode from a metal that is easily
oxidised; forming a ferroelectric film substantially over the first
electrode; forming a second electrode on the ferroelectric film; and wherein the step of forming the ferroelectric film
comprises constituting multiple crystal grain layers by
assembling crystal grains by means of grain boundaries along a
surface of the first electrode.
Claim 6
Dependent Claim
158 words
The method as claimed in Claim 5, wherein the step of
forming the ferroelectric film comprises; depositing a first oxide layer comprising at least one
element of the constituent elements of the ferroelectric film; forming a first ferroelectric material layer comprising a
surplus of a constituent element of the ferroelectric film on
the oxide layer; forming a lower crystal grain layer by heating at a
temperature at which surface precipitates mainly composed of
said constituent element are substantially lost; depositing a second oxide layer of at least one element of
the constituent elements of the ferroelectric film on the lower
crystal grain layer; forming a second ferroelectric film layer containing a
surplus of a constituent element of the ferroelectric film on
the lower crystal grain layer on which the second oxide layer is
deposited; forming an upper crystal grain layer by heating at a
temperature at which surface precipitates mainly composed of the
constituent element are substantially lost.
Claim 7
Dependent Claim
31 words
The method as claimed in Claim 6, wherein the steps of
depositing the second oxide layer, forming the second
ferroelectric film layer, and forming an upper crystal grain
layer are repeated.
Claim 8
Independent Claim
21 words
The method as claimed in any of Claims 5 to 7, further
comprising; forming the ferroelectric film from lead zirconate
titanate.
Claim 9
Independent Claim
31 words
The method as claimed in any of Claims 6 to 8, wherein the
steps of depositing the first oxide layer and forming the second
ferroelectric film layer comprise depositing titanium oxide.
Claim 10
Independent Claim
36 words
The method as claimed in any of Claims 6 to 9, wherein the
steps of forming the first and second ferroelectric layers
comprise forming an amorphous layer of lead zirconate titanate
containing a surplus of lead.
Claim 11
Independent Claim
48 words
The method as claimed in any of Claims 6 to 10, wherein the
steps of forming the lower and upper crystal grain layer
comprise annealing said capacitor at a temperature at which
surface precipitates substantially composed of surplus lead are
substantially lost; and post-annealing said crystal grain layer.
Claim 12
Dependent Claim
66 words
The method as claimed in Claim 10 or Claim 11, wherein the
step of forming an amorphous layer of lead zirconate titanate
containing a surplus of lead comprises forming a layer in which
the lead content of the amorphous layer is 1.02 - 1.50 times, at
an atomic ratio, the total amount zirconium and titanium, and
performing the annealing and post-annealing at 625 Celsius or
higher.
Claim 13
Independent Claim
64 words
The method as claimed in any of Claims 8 to 12 further
comprising; forming a titanium oxide on the lower electrode; forming the ferroelectric film using a sol-gel process in
which a precursor solution of lead zirconate titanate is
distributed on the lower electrode; forming an amorphous layer of lead zirconate titanate by
heating the precursor solution; and crystallising the amorphous layer by annealing.
Claim 14
Independent Claim
34 words
The method as claimed in any of Claims 5 to 13, wherein the
steps of forming the first and second oxide layers comprises
depositing an oxide to a thickness of 0.01 - 10 nm.
Claim 15
Independent Claim
25 words
A method of fabricating a memory cell comprising at least
one capacitor is formed according to the method of any of Claims
5 to 14.