Semiconductor device manufacturing: process – Making passive device – Trench capacitor
Reexamination Certificate
2003-05-09
2004-11-02
Fourson, George (Department: 2823)
Semiconductor device manufacturing: process
Making passive device
Trench capacitor
C438S240000, C438S386000
Reexamination Certificate
active
06812110
ABSTRACT:
TECHNICAL FIELD
The invention pertains to capacitor constructions and methods of forming capacitor constructions. The invention also pertains to methods of forming constructions comprising dielectric materials.
BACKGROUND OF THE INVENTION
There is a continuing interest to incorporate oxide dielectrics into semiconductor constructions. Among the dielectrics that are of particular interest are those represented by the formula MO
z
, where M represents a metal, O is oxygen, and z is a number greater than 0, and typically less than or equal to 8. The metal can be a transition metal, such as, for example, hafnium, or a non-transition metal, such as, for example, aluminum. The dielectric materials can be useful in, for example, capacitor constructions.
A difficulty in utilizing metal oxide dielectrics (MO
z
) is that diffusion can occur between the dielectric materials and structures proximate to the dielectric materials, and such diffusion can adversely affect properties of the dielectric material and/or the structures proximate to the dielectric material. For instance, if a conductive structure comprises conductively-doped silicon and MO
z
is formed directly on the conductively-doped silicon, oxygen from the MO
z
can interact with the silicon to oxidize the silicon. The oxidized silicon will no longer have the desired conductive properties of conductively-doped silicon.
The problems discussed above can be alleviated, and even prevented, through utilization of a metal nitride barrier layer. The metal nitride can be represented as MN
y
, where M is metal, N is nitrogen, and y is a number greater than 0 and typically less than 8. The metal nitride is frequently referred to as a diffusion barrier layer, as the metal nitride alleviates, and frequently even prevents, diffusion to and/or from a metal oxide dielectric. U.S. Pat. No. 5,741,721 describes exemplary structures in which metal oxide dielectric materials are formed over metal nitride barrier layers. U.S. Pat. No. 5,741,721 specifically describes processes in which a metal nitride layer is formed over a semiconductor substrate, and subsequently a surface of the metal nitride layer is oxidized to form a metal oxide dielectric material.
The processing described in U.S. Pat. No. 5,741,721 can be difficult to incorporate into various semiconductor fabrication processes. Accordingly, it would be desirable to develop alternative methods for forming metal oxide dielectric material adjacent diffusion barrier layers.
SUMMARY OF THE INVENTION
In one aspect, the invention encompasses a method of forming a construction which includes a dielectric material. A layer comprising one or more of MC
x
, MB
q
and MN
y
is formed, with M being a metal, and with q, x and y being numbers greater than 0. A dielectric material comprising MO
z
is deposited over and directly against the layer, with z being a number greater than 0. In particular aspects, the layer and the dielectric material can comprise a metal (for example, hafnium or aluminum) in common.
In one aspect, the invention pertains to a method of forming a capacitor construction. A first electrically conductive material is formed over a semiconductor substrate. An intermediate layer is formed over the first electrically conductive material. The intermediate layer predominantly comprises a composition of a metal and one or more of boron, nitrogen and carbon. A dielectric layer is deposited over and directly against the intermediate layer, with the dielectric layer predominantly comprising a composition of the metal and oxygen. A second electrically conductive material is formed over the dielectric layer. The second electrically conductive material is capacitively connected with the first electrically conductive material.
In one aspect, the invention encompasses a capacitor construction. The construction includes a first electrically conductive material, and a first intermediate layer over the first electrically conductive material. The first intermediate layer predominantly comprises a composition of aluminum and one or more of boron, nitrogen and carbon. A dielectric material is over and directly against the first intermediate layer. The dielectric material predominantly comprises a composition of aluminum and oxygen. A second intermediate layer is over the dielectric material, with the second intermediate layer predominantly comprising the composition of aluminum and one or more of boron, nitrogen and carbon. A second electrically conductive material is over the second intermediate layer. The second electrically conductive material is capacitively connected with the first electrically conductive material. The capacitor construction can be incorporated into a dynamic random access memory (DRAM) cell. The DRAM cell can be utilized in an electronic system.
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Basceri Cem
Gealy F. Daniel
Sandhu Gurtej S
Fourson George
Micro)n Technology, Inc.
Toledo Fernando L.
Wells St. John P.S.
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