Single-crystal – oriented-crystal – and epitaxy growth processes; – Forming from vapor or gaseous state – With decomposition of a precursor
Reexamination Certificate
1999-08-09
2001-08-07
Beck, Shrive (Department: 1762)
Single-crystal, oriented-crystal, and epitaxy growth processes;
Forming from vapor or gaseous state
With decomposition of a precursor
C117S089000, C117S102000
Reexamination Certificate
active
06270572
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing a thin film, and more particularly, to a method for manufacturing a thin film by atomic layer deposition (ALD).
2. Description of the Related Art
A thin film is typically used for a dielectric of a semiconductor device, a transparent conductor of a liquid-crystal display, or a protective layer of an electroluminescent thin film display. The thin film is formed through evaporation, chemical vapor deposition or ALD.
ALD is a surface controlled process, and uses two dimensional layer by layer deposition. In the ALD method, the deposition is performed in a surface kinetic regime. Thus, the step coverage is excellent. Also, a reactant is decomposed through chemical exchange by periodically supplying the reactant without pyrolysis so that the resultant film has high density and precise stoichiometry. Also, by-products generated by the chemical exchange are gasses that can be easily removed. Accordingly, so a chamber can be easily cleaned. The temperature is the only process variable in the ALD method, so the process is easily controlled and maintained.
However, in the conventional ALD, since enough reactant is not adsorbed on the surface of a substrate, a defect such as a pinhole is generated in the thin film. Therefore, the physical characteristics of the thin film, such as the film density, deteriorate. Also, in the conventional ALD, since a chemical ligand is not substantially removed, it is not possible to obtain a precise stoichiometric thin film.
SUMMARY OF THE INVENTION
To solve the above problems, the present invention provides a method for manufacturing a precise stoichiometric thin film having a high film density by atomic layer deposition.
Accordingly, the method includes the step of chemically adsorbing a first reactant onto a substrate by injecting the first reactant into a chamber which the substrate is loaded. A physisorbed first reactant on the chemically adsorbed first reactant is removed by purging or pumping the chamber. After the first reactant is densely chemically adsorbed onto the substrate by injecting the first reactant into the chamber, the physisorbed first reactant on the dense chemisorbed first reactant is removed by purging or pumping the chamber. A second reactant is chemically adsorbed onto the surface of the substrate by injecting the second reactant into the chamber. A physisorbed second reactant on densely chemisorbed first reactant and the second reactant is removed by purging or pumping the chamber. A solid thin film is formed by chemical exchange through densely adsorbed second reactant on the substrate by re-injecting the second reactant into the chamber.
After densely adsorbing the second reactant, the physically adsorbed second reactant and residuals generated during the chemical exchange can be removed by purging or pumping the chamber. The processes of injecting the second reactant and removing the physically adsorbed second reactant and the residuals can be sequentially repeated two or more times. The processes of injecting the first reactant and removing the physically adsorbed first reactant can be sequentially repeated two or more times. The substrate is (
100
) silicon substrate. The first reactant and the second reactant are comprised of an atom and a chemical ligand for constructing the solid thin film.
The solid thin film is comprised of a material selected from the group consisting of a single element, an oxide of a single element, a composite oxide, a nitride of a single element, and a composite nitride. The single element is selected from the group consisting of Mo, Al, Cu, Ti, Ta, Pt, Ru, Rh, Ir, W, and Ag. The oxide of a single element is selected from the group consisting of Al
2
O
3
, TiO
2
, Ta
2
, O
5
, ZrO
2
, HfO
2
, Nb
2
O
5
, CeO
2
, Y
2
O
3
, SiO
2
, In
2
O
3
, RuO
2
, and IrO
2
. The composite oxide is selected from the group consisting of SrTiO
3
, PbTiO
3
, SrRuO
3
, CaRuO
3
, (Ba,Sr)TiO
3
, Pb(Zr,Ti)O
3
, (Pb.La)(Zr,Ti)O
3
, (Sr,Ca)RuO
3
, In
2
O
3
doped with Sn, In
2
O
3
doped with Fe, and In
2
O
3
doped with Zr. The nitride of a single element is one selected from the group consisting of SiN, NbN, ZrN, TaN, Ya
3
N
5
, AlN, GaN, WN, and BN. The composite nitride is one selected from the group consisting of WBN, WSiN, TiSiN, TaSiN, AlSiN, and AlTiN.
According to the present invention, it is possible to obtain a precise stoichiometric thin film having a high film density, since the first reactant and the second reactant are densely adsorbed and the impurities are substantially removed by pumping or purging.
REFERENCES:
patent: 5851849 (1998-12-01), Comizzoli et al.
Kim Yeong-kwan
Lee Sang-in
Lee Sang-Min
Park Chang-soo
Beck Shrive
Cleveland Michael
Marger & Johnson & McCollom, P.C.
Samsung Electronics Co,. Ltd.
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