GB2391555A - Vapour phase deposition of silicate and oxide films - Google Patents
Vapour phase deposition of silicate and oxide films Download PDFInfo
- Publication number
- GB2391555A GB2391555A GB0318390A GB0318390A GB2391555A GB 2391555 A GB2391555 A GB 2391555A GB 0318390 A GB0318390 A GB 0318390A GB 0318390 A GB0318390 A GB 0318390A GB 2391555 A GB2391555 A GB 2391555A
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- rare earth
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- silicate
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
- C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
- C23C16/40—Oxides
- C23C16/401—Oxides containing silicon
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- Inorganic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Vapour Deposition (AREA)
- Formation Of Insulating Films (AREA)
Abstract
Methods of depositing thin films of rare earth or Group IIIB element silicates or oxides by chemical vapour deposition use a precursor of the general formula: <CHE>M[N(SiR3)2]3</CHE> wherein R is an alkyl group and M is a rare earth element including La, Pr, Ce, Gd and Nd or a Group IIIB element such as Sc or Y. As an alternative atomic layer deposition (ALD) may be used. Specific examples describe the deposition of lanthanum silicate and praseodymium silicate.
Description
1 2391 555
Title: Vapour phase deposition of silicate and oxide films DESCRIPTION
This invention concerns deposition of lanthanide silicate and oxide films. Thin films of Lanthanum oxide, La2O3, and lanthanum silicate, LaSixOy, have potential applications as alternative gate dielectric layers in silicon-based field effect transistors. As device dimensions continue to shrink,
electron tunnelling and high leakage currents present serious obstacles to future device reliability, making it necessary to replace existing SiO2-based gate dielectrics with higher permittivity oxide materials such as La2O3 and LaSixOy. La2O3 has a variety of other useful physical characteristics such as high mechanical stability and good optical transparency from ultraviolet to infrared, leading to applications in protective and optical coatings. Lanthanum oxide is also a component of the ferroelectric oxide (Pb,La)(Zr,Ti) Or (PLZT) used in DRAM's, and is present on the conducting oxides lanthanum manganate, LaMnO3, and lanthanum nickelate, LaNiO3, potential electrode materials in ferroelectric memory devices.
A number of methods have been used for the deposition of La-
containing oxides. For instance LaOx films have been deposited by atomic beam deposition on a Si (100) substrate (S. Guha, E. Cartier, M.A. Gribelyuk, N.A. Borjarczuk, M.A. Copel, Appl. Pl7ys. Leff., 2000, 77, 2710), whilst deposition of LaSixOy has been investigated by the deliberate oxidation of thin LaOx films (20A) grown by atomic beam deposition on a thermal SiO2
layer (23A) (M. Copel, E. Cartier, F.M. Ross, Appl. Phys. Left., 2001, 78, 1 607).
Metalorganic chemical vapour deposition (MOCVD) and atomic layer deposition (ALE)) have a number of potential advantages over other deposition techniques, such as good composition control, high film densities and deposition rates and excellent conformal step coverage. Despite this, the growth of high quality La2O3 or LaSixOy films by these techniques has not yet been demonstrated. Lanthanum oxide films grown from the p-diketonate precursors La(thd)3 (tied = 2,2,6,6tetramethylheptane-3,5-dionate) and La(acac)3 (acac is acetylacetonate) typically show heavy carbon contamination (Y. Shiokawa, R. Amano, A. Nomura, M. Yagi, J. Radioanal.
Nucl. Chem., 1991, 152, 373, A. Weber, H. Suhr, Mod. Phys. Leff., 1989, B3, 1001, M.V. Cabanas, C.V. Ragel, F. Conde, J.M. Gonzalez-Calbet, M. Vallet-
Regi, Solid State lonics, 1997, 101-103, 191, M. Nieminen, M. Putkonen, L. Niinisto, Appl. Suff. Sci., 2001, 74, 155). There are no reports of the deposition of LaSixOy by MOCVD.
There is thus an urgent requirement for new, improved precursors for the MOCVD of lanthanum-containing oxides, but there are few precursors available with the appropriate stability and volatility. There are no suitable lanthanum alkoxide precursors due to the large ionic radius of La3+, which results in many of its simple alkoxide complexes being polymeric or oligomeric with low volatility. Recently there has been a growing use of metal alkylamides, M(NR2)x, for the MOCVD of dielectric and ferroelectric oxides but simple lanthanum alkylamides such as La(NMe2) 3 are unstable and non-
volatile.
An object of this invention is to provide a chemical vapour deposition process for the growth of high purity silicate and oxide films, especially of lanthanum but also of other rare earth elements and Group IIIB elements.
It has been surprisingly found that pure lanthanum silicate thin films (carbon and nitrogen not detected by Auger electron spectroscopic analysis) can be deposited by liquid injection MOCVD using the precursor tris-(bis-
trimethylsilyl)amido-lanthanum, La[N(SiMe3)2]3, in the presence of oxygen but without the addition of a separate silicon precursor.
Accordingly in a first aspect the invention there is provided a method of depositing a thin film of a rare earth or Group IIIB element silicate by chemical vapour deposition in the presence of oxygen using a precursor of the general formula: M[N(SiR3)2]3 wherein R is an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms, and M is a rare earth element including La, Pr, Ce, Gd and Nd or a Group IIIB element such as Sc or Y. The method of the first aspect of the invention may also be carried out with the addition of a separate silicon precursor.
According to a second aspect the invention provides a method of depositing a thin film of a rare earth or Group IIIB element oxide by chemical vapour deposition using a precursor of the general formula: M[N(SiR3)2]3 with the addition of an alcohol (ROM) in the gas phase, wherein R is an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms, and M is a rare
earth element including La, Pr, Ce, Gd and Nd or a Group IIIB element such as Sc or Y. According to a third aspect of the invention there is provided a method of depositing rare earth or Group IIIB element silicate or oxide by atomic layer deposition (ALD) using a precursor of the general formula: M[N(SiR3)2]3 wherein R is an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms, and M is a rare earth element including La, Pr, Ce, Gd and Nd or a Group IIIB element such as Sc or Y. Preferably, rare earth or Group IIIB oxides will be deposited using ALD in the presence of water as an oxidant.
The method of any aspect of the invention may be used to deposit mixed metal oxide layers containing elements M by combination of the element M precursor with appropriate other metal precursors.
The method according to the second aspect of the invention may be achieved by the evaporation of a hydrocarbon solution of the alcohol, injected separately to the M[N(SiR3)2]3 precursor.
The method according to the third aspect of the invention may be achieved by injecting separate alternate pulses of M[N(SiR3)2]3 and J LO or ROW into the reaction chamber.
Preferred precursors for use according to the invention have the following general formula: M[N(SiR3)2]3
wherein R is alkyl, preferably Me, but may also be Et, Pr', Bun or But, provided the resulting complex retains sufficient stability and volatility for use in MOCVD.
For the growth of oxides, such as from La[N(SiR3)2]3 and ROH precursors, the added alcohol ROH is preferably iso-propanol, Pr'OH, but other alcohols may also be used, such as MeOH, EtOH, BunOH and BubH.
Methods of the invention may be used in depositing element M silicate, element M oxide and mixed metal oxide layers containing element M by conventional MOCVD, in which the precursor is contained in a metalorganic bubbler, or preferably, by liquid injection MOCVD, in which the precursor is dissolved in an appropriate inert organic solvent and then evaporated into the vapour phase using a heated evaporator.
The invention will now be further described with reference to the accompanying drawings, in which: Figure 1 is a plot of lanthanum silicate growth rate with substrate temperature; and Figure 2 is an Arrhenius plot of lanthanum silicate films.
The invention will also be further described by means of the following Examples.
Example 1
Preparation of La[N(SiMe3)]3 The precursor was synthesised by a modification of published procedure (D.C. Bradley, J.S. Ghotra, F.A. Hart, d. Chem. Soc., Dalton Trans., 1973, 1021) from the reaction between anhydrous LaCI3 (1 mol equiv.) and LiN(SiMe3)2 (2.8 mol equiv.) in tetrahydrofuran. After boiling
under reflex for 5hours the reaction mixture was allowed to cool and volatiles were removed in vacuo to give an off-white solid. The product was extracted from LiCI using petroleum ether and pure La[N(SiMe3)2]3 (m. pt. 145-149 C) was obtained as colourless needles by concentration and cooling (-5OC) of the petroleum ether solution (yield 70% based on LiN(SiMe3)2). The complex was confirmed to be La[N(SiMe3)2]3 by elemental microanalysis and by 'H NMR spectroscopy, which gave identical data to published values.
Example 2
Thin films of lanthanum silicate were deposited on Si(100) substrates by low pressure liquid injection MOCVD by the evaporation of a solution of La[N(SiMe3)2]3 in dry toluene in the presence of oxygen reactant gas. The films were deposited over the temperature range 350 - 600 C. A summary of
growth conditions used to deposit lanthanum silicate by liquid injection MOCVD from a toluene solution of La[N(SiMe3)2]3 is given in Table 1.
Table 1
Reactor pressure 6 mbar Evaporator temperature 1 80 C Substrate temperature 350-600 C Precursor solution concentration 0.1 M Precursor solution injection rate 8 cm3 he.
Argon flow rate 400 cm3 min' Oxygen flow rate 100 cm3 min' Substrates Si(1 00)
The atomic composition of the films was determined by Auger electron spectroscopy (AES), and the results are summarized in Table 2. The data shows that all films are lanthanum silicate. It is significant that carbon and nitrogen were not detected in the films (estd. detection limit 0.5-1 atomic %).
Table 2
Composition (at. %) Atomic Film no. Deposition Depth La Si temperature ( C) 1 350 A 30.0 9.O 61.0
B 30.4 8.6 61.0
2 400 A 28.2 8.5 63.3
B 29.7 9.5 60.8
3 450 A 37.4 10.1 52.5
B 35.0 14.5 50.5
4 500 A 33.0 15.2 51.8
5 550 A 33.6 10.8 55.6
6 600 A 25.6 12.7 61.7
B 25.1 11.7 63.2
_ Sub-surface depths, A = 150 nm, B = 600 nm.
Analysis of the films by scanning electron microscopy (SEM) showed that all the as-grown lanthanum silicate films were amorphous.
The variation in La-silicate growth rate with substrate temperature is shown in Figure 1 and an Arrhenius plot of this data, shown in Figure 2, gives an approximate activation energy for the silicate growth process (Ea) of 47 kJ mold.
Example 3.
Preparation of Pr[N(SiMe3)]3 Pr[N(SiMe3)2]3 was prepared in an analogous manner to La[N(SiMe3)2]3, from the reaction between PrCI3 (1 mol equiv.) and LiN(SiMe3)2 (2.8 mol equiv.) in tetrahydrofuran.
Example 4
Thin films of praseodymium silicate were deposited on Si(100) substrates by low pressure liquid injection MOCVD by the evaporation of a solution of Pr[N(SiMe3)2]3 in dry toluene in the presence of oxygen reactant gas. The films were deposited over the temperature range 350 - 550 C. A summary of growth conditions is given in Table 3.
Table 3.
Reactor pressure 2 mbar Evaporator temperature 1 80 C Substrate temperature 350-550 C Precursor solution concentration 0.1 M in toluene Precursor solution injection rate 8 cm3 he.
Argon flow rate 400 cm3 mint, Oxygen flow rate 100 cm3 mint' Substrates Si(1 00) Run time 1 hr.
Typical growth rates 0.07 - 0.42 rum fur-'
Claims (13)
1. A method of depositing a thin film of a rare earth or Group IIIB element silicate by chemical vapour deposition in the presence of oxygen using a precursor of the general formula: M[N(SiR3)2]3 wherein R is an alkyl group and M is a rare earth element including La, Pr, Ce, Gd and Nd or a Group IIIB element such as Sc or Y.
2. A method as claimed in claim 1, wherein R is an alkyl group having 1 to 4 carbon atoms.
3. A method as claimed in claim 1 carried out with the addition of a separate silicon precursor.
4. A method of depositing a thin film of a rare earth or Group IIIB element oxide by chemical vapour deposition using a precursor of the general formula: M[N(SiR3)2]3 with the addition of an alcohol (ROM) in the gas phase, wherein R is an alkyl group and M is a rare earth element including La, Pr, Ce, Gd and Nd or a Group IIIB element such as Sc or Y.
5. A method as claimed in claim 4, wherein R is an alkyl group having 1 to 4 carbon atoms
6. A method as claimed in claim 4 or 5 carried out by the evaporation of a hydrocarbon solution of the alcohol, injected separately to the M[N(SiR3)2]3 precursor.
7. A method as claimed in claim 4, 5 or 6, wherein the alcohol is isopropanol.
8. A method of depositing rare earth or Group IIIB element silicate or oxide by atomic layer deposition (ALD) using a precursor of the general formula: M[N(SiR3k]3 wherein R is an alkyl group and M is a rare earth element including La, Pr, Ce, Gd and Nd or a Group IIIB element such as Sc or Y.
9. A method as claimed in claim 8, wherein R is an alkyl group having 1 to 4 carbon atoms.
10. A method as claimed in claim 8 or 9 carried out in the presence of water as an oxidant.
11. A method as claimed in claim 8, 9 or 10 achieved by injecting separate alternate pulses of M[N(SiR3)2]3 and H2O or ROH into the reaction chamber.
12. A method as claimed in any one of claims 1 to 11, wherein mixed metal oxide layers containing elements M are deposited by combination of the element M precursor with appropriate other metal precursors.
13. A method of depositing a thin film of a rare earth or Group IIIB element silicate or oxide substantially as hereinbefore described with reference to any one of the foregoing Examples.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0218544A GB0218544D0 (en) | 2002-08-09 | 2002-08-09 | Deposition of lanthanum silicate and lanthanum oxide films |
| GB0306028A GB0306028D0 (en) | 2003-03-17 | 2003-03-17 | Vapour phase deposition of silicate and oxide films |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0318390D0 GB0318390D0 (en) | 2003-09-10 |
| GB2391555A true GB2391555A (en) | 2004-02-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0318390A Withdrawn GB2391555A (en) | 2002-08-09 | 2003-08-06 | Vapour phase deposition of silicate and oxide films |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2391555A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101792469A (en) * | 2010-03-05 | 2010-08-04 | 南京航空航天大学 | Ultrasonic assisted method for synthesizing lanthanum tris[bis(trimethylsilyl)amide] |
| EP2220266A1 (en) * | 2007-11-06 | 2010-08-25 | Linde Aktiengesellschaft | Solution based lanthanum precursors for atomic layer deposition |
| JP2017019777A (en) * | 2015-07-07 | 2017-01-26 | 三星電子株式会社Ｓａｍｓｕｎｇ Ｅｌｅｃｔｒｏｎｉｃｓ Ｃｏ．，Ｌｔｄ． | Lanthanum compound, method of producing the same, lanthanum precursor composition, method of forming thin film using the same, and method of producing integrated circuit device |
| CN106591800A (en) * | 2015-10-16 | 2017-04-26 | Asm Ip控股有限公司 | Method of Implementing atomic layer deposition for gate dielectrics |
| CN110272438A (en) * | 2018-03-16 | 2019-09-24 | 三星电子株式会社 | Lanthanum compound and the method for forming film and integrated circuit device using the lanthanum compound |
| US10913754B2 (en) | 2015-07-07 | 2021-02-09 | Samsung Electronics Co., Ltd. | Lanthanum compound and methods of forming thin film and integrated circuit device using the lanthanum compound |
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|---|---|---|---|---|
| US5583205A (en) * | 1993-11-12 | 1996-12-10 | Florida State University | Metalorganic chemical vapor deposition method for depositing f-series metal or nitrogen and metal amides for use in mocvd |
| GB2354762A (en) * | 1998-01-23 | 2001-04-04 | Advanced Tech Materials | Tantalum amide precursors for deposition of tantalum nitride on a substrate |
| WO2002079211A1 (en) * | 2001-03-30 | 2002-10-10 | Advanced Technology Materials, Inc. | Metalloamide and aminosilane precursors for cvd formation of dielectric thin films |
| WO2003035926A2 (en) * | 2001-10-26 | 2003-05-01 | Epichem Limited | Improved precursors for chemical vapour deposition |
-
2003
- 2003-08-06 GB GB0318390A patent/GB2391555A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5583205A (en) * | 1993-11-12 | 1996-12-10 | Florida State University | Metalorganic chemical vapor deposition method for depositing f-series metal or nitrogen and metal amides for use in mocvd |
| GB2354762A (en) * | 1998-01-23 | 2001-04-04 | Advanced Tech Materials | Tantalum amide precursors for deposition of tantalum nitride on a substrate |
| WO2002079211A1 (en) * | 2001-03-30 | 2002-10-10 | Advanced Technology Materials, Inc. | Metalloamide and aminosilane precursors for cvd formation of dielectric thin films |
| WO2003035926A2 (en) * | 2001-10-26 | 2003-05-01 | Epichem Limited | Improved precursors for chemical vapour deposition |
Non-Patent Citations (2)
| Title |
|---|
| JP10256276 A & Japio abstract of JP10256276 A * |
| JP2002088475 A & Japio abstract of JP2002088475 A * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2220266A1 (en) * | 2007-11-06 | 2010-08-25 | Linde Aktiengesellschaft | Solution based lanthanum precursors for atomic layer deposition |
| EP2220266A4 (en) * | 2007-11-06 | 2012-05-02 | Linde Ag | Solution based lanthanum precursors for atomic layer deposition |
| CN101792469A (en) * | 2010-03-05 | 2010-08-04 | 南京航空航天大学 | Ultrasonic assisted method for synthesizing lanthanum tris[bis(trimethylsilyl)amide] |
| CN101792469B (en) * | 2010-03-05 | 2012-06-06 | 南京航空航天大学 | Ultrasonic assisted method for synthesizing lanthanum tris[bis(trimethylsilyl)amide] |
| JP2017019777A (en) * | 2015-07-07 | 2017-01-26 | 三星電子株式会社Ｓａｍｓｕｎｇ Ｅｌｅｃｔｒｏｎｉｃｓ Ｃｏ．，Ｌｔｄ． | Lanthanum compound, method of producing the same, lanthanum precursor composition, method of forming thin film using the same, and method of producing integrated circuit device |
| US10752645B2 (en) | 2015-07-07 | 2020-08-25 | Samsung Electronics Co., Ltd. | Method of forming a thin film |
| US10913754B2 (en) | 2015-07-07 | 2021-02-09 | Samsung Electronics Co., Ltd. | Lanthanum compound and methods of forming thin film and integrated circuit device using the lanthanum compound |
| CN106591800A (en) * | 2015-10-16 | 2017-04-26 | Asm Ip控股有限公司 | Method of Implementing atomic layer deposition for gate dielectrics |
| CN110272438A (en) * | 2018-03-16 | 2019-09-24 | 三星电子株式会社 | Lanthanum compound and the method for forming film and integrated circuit device using the lanthanum compound |
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| Publication number | Publication date |
|---|---|
| GB0318390D0 (en) | 2003-09-10 |
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| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |