Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – Insulated gate formation
Reexamination Certificate
1999-01-05
2001-10-23
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
Insulated gate formation
C435S091500, C435S091500, C435S091500, C435S091500, C435S091500, C435S091500
Reexamination Certificate
active
06306742
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of semiconductor processing and more particularly to a method for forming a dielectric layer in an integrated circuit.
BACKGROUND OF THE INVENTION
A desire to increase the speed and density of integrated circuits (ICs) has led to transistor scaling accompanied by progressive reductions in the thickness of the gate oxide. A thinner gate oxide provides greater drive current, thereby increasing speed. Also, a thinner gate oxide provides greater control over the channel charge, thereby reducing short channel effects. However, thinner gate oxides present greater problems of manufacturability, quality, and reliability.
One way to avoid the problems of a thinner gate oxide but achieve the desired capacitive effect is to replace the gate oxide with a gate dielectric that has a greater dielectric constant than silicon dioxide. Paraelectric materials have dielectric constants that are usually at least two orders of magnitude above that of silicon dioxide, but several problems limit their use as gate dielectrics. One such problem is illustrated in
FIGS. 1
a
and
1
b
.
FIG. 1
a
is a cross sectional illustration of a prior dielectric system before any high temperature processing has occurred, such as source/drain dopant activation, and
FIG. 1
b
is a cross sectional illustration of the same dielectric system after high temperature processing has occurred. During these high temperature processes, oxygen diffuses from gate dielectric
101
to interface
102
between gate dielectric
101
and gate electrode
103
, and to interface
104
between gate dielectric
101
and channel
105
. The diffused oxygen forms oxide layer
106
at these interfaces, decreasing the overall capacitance of the dielectric system and partially counteracting the effect of the high dielectric constant paraelectric material.
Therefore, a better way to form a high dielectric constant insulator in the fabrication of an integrated circuit is desired.
SUMMARY OF THE INVENTION
A method for forming an insulator with a high dielectric constant in the fabrication of an integrated circuit is disclosed. First, the substrate on which the integrated circuit is being fabricated is nitridated. Then, a dielectric layer which has a dielectric constant higher than that of silicon dioxide is formed.
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Doyle Brian
Lee Jack
Berry Renee R.
Intel Corporation
Nelms David
Winkle Robert G.
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