JP5464775B2 - Method for producing metal oxide film at low temperature - Google Patents

Description

  This application is US patent application Ser. No. 10 / 003,749, filed Oct. 23, 2001, and is now a continuation-in-part of US Pat. No. 6,743,475, which is incorporated by reference It claims the priority of Finnish patent application No. 20002323 filed on Oct. 23, 2000 under section 119 (a).

  The present invention relates to a method for producing a metal oxide film by an ALD method. According to a preferred method, the metal oxide film is produced at a low temperature by binding the metal compound to a substrate and converting the metal compound to a metal oxide.

Dielectric thin films having a high dielectric constant (permeability) have many applications in the field of microelectronics. For example, to maintain the required capacitance when reducing the size of the capacitors, they can replace the SiO ₂ and Si ₃ N ₄ currently used in DRAM memories.

Al ₂ O ₃ films suitable for surface passivation have been previously prepared by physical methods such as sputtering. Problems with films produced by sputtering were non-uniformity of the resulting film and pinholes formed in the film. These pinholes can form a water diffusion path through the membrane.

US Pat. No. 6,124,158 discloses a method for reducing carbon contamination of Al ₂ O ₃ thin films deposited by ALD. The ALD method uses an organoaluminum precursor and water. In order to reduce carbon contamination, ozone is introduced into the reaction chamber at least every three cycles. Since the aluminum oxide film deposited at 190 ° C. or lower has a low density and is not reproducible, the method is limited.

In addition, the ALD method is used to manufacture an Al ₂ O ₃ film using aluminum alkoxide, trimethylaluminum (TMA) or AlCl ₃ as an aluminum source material and water, alcohol, H ₂ O ₂ or N ₂ O as an oxygen source material. Was also used. Al ₂ O ₃ films from TMA and water were deposited at temperatures in the range of 150-400 ° C. Generally, the temperature was 150 ° C to 300 ° C. The resulting film had a uniform thickness and no pinholes. However, there was a problem with the film density at the low end of the deposition temperature range.

US Pat. No. 6,124,158 US Pat. No. 6,015,590 N. N. Greenwood and A.M. Ernshaw, “Chemistry of the Elements”, Pergamon Press Ltd. , Oxford, England 1986

  In applications where the substrate is sensitive to water, the use of water as an oxygen source material is impractical, so organic polymers or low molecular weights such as organic light-emitting displays or organic EL displays also known as organic light-emitting diodes (OLEDs) In applications involving organic molecules, the deposition temperature is preferably less than 150 ° C. Furthermore, substrates with organic layers are typically exposed to alkaline solutions during certain processing methods, which impose stringent requirements on the properties of the protective layer on the organic surface. Pinholes are never allowed in the protective layer. Therefore, there is a need for a method for producing a metal oxide film by ALD at a low temperature using an oxygen source other than water.

  The present invention is based on the surprising discovery that high quality metal oxide thin films can be grown by ALD at substrate temperatures as low as about 50 ° C. Another surprising discovery is that ozone can be used in the deposition process without destroying the properties of the substrate including the organic layer. A dense pinhole-free thin film layer can be generated on the substrate surface by ALD very quickly, protecting the sensitive material below the surface from the surrounding gas atmosphere.

  According to one aspect of the present invention, a method is provided for depositing a thin film of metal oxide on a substrate by an atomic layer deposition method comprising a plurality of cycles. Each cycle includes supplying a first reactant containing a gaseous metal compound and supplying a gaseous second reactant containing an oxygen source other than water. The second reactant converts the portion of the first reactant absorbed on the substrate into a metal oxide. The substrate is preferably kept below 190 ° C. during the ALD process.

  The preferred embodiment provides many significant advantages. For example, it is possible to produce a good quality metal film at low temperatures according to the present invention.

  A high-density dielectric thin film can be used for surface passivation that is unacceptable at high temperatures. Their surfaces include, for example, polymer films. If a water free oxygen source is used, water sensitive surfaces can also be passivated.

  Furthermore, a dielectric film having a high-density structure including a metal oxide thin film can be used as a buffer layer between functional films including at least one organic film. Therefore, the dielectric film prevents any reaction or diffusion between the functional films.

Definitions For purposes of the present invention, “ALD process” refers to a process in which the deposition of a thin film from a gaseous source chemical onto a surface is based on a sequential self-saturated surface reaction. The principle of the ALD method is disclosed in, for example, US Pat. No. 6,015,590 (Patent Document 2).

  "Reaction space" is used to refer to a reactor or reaction chamber whose conditions can be adjusted so that a thin film can be deposited on a substrate by ALD.

  “Thin film” is used to refer to a film that grows from an element or compound that is transported from a source as a separated ion, atom, or molecule to a substrate via a vacuum, gas phase, or liquid phase. The thickness of the film depends on the application and ranges for example from a single molecular layer (about 0.5 nm) to 1,000 nm or more.

  “Metal oxide” is used to refer to a thin film comprising at least one metal bonded to oxygen. The metal is preferably selected from the group consisting of Group IIA, IIIB, IVB, VB, and VIB metals. More preferably, the metal is Mg, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ti, Zr, Hf, V, Nb. , Ta, Cr, Mo, W are selected.

The thin film containing a metal oxide can be, for example, without limitation, a single metal oxide (eg, Al ₂ O ₃ , Ta ₂ O ₅ , TiO ₂ , ZrO ₂ , or HfO ₂ ), a solid solution of a metal oxide (Eg, Ta _2x Nb _2-2x O ₅ or Ti _m Zr _1-m O ₂ ), ternary metal oxides (eg, aluminum titanate Al ₂ TiO ₅ or hafnium silicate HfSiO ₄ ), doped metal oxides (Eg, Al ₂ O ₃ : Ta or TiO ₂ : Ta) and layered or nanolaminate metal oxides (eg, Al ₂ O ₃ / Ta ₂ O ₅ or Al ₂ O ₃ / TiO ₂ ) it can.

A “dense” structure is one that has less leakage current through it when comparing two basic films of the same basic material, such as two thin films of Al ₂ O ₃ deposited by different methods, Alternatively, it means a thin film having a small ion or gas permeability.

Deposition Method A metal oxide thin film that functions as a dielectric or passivation layer, such as Al ₂ O ₃ , Ta ₂ O ₅ , TiO ₂ , or HfO ₂ , is grown on a desired substrate by ALD. The substrate is preferably heated to the processing temperature and selected from the range of about 50 ° C to about 190 ° C. More preferably, the processing temperature is less than about 150 ° C, more preferably less than about 125 ° C, and even more preferably less than about 100 ° C.

  The metal source chemical used in the ALD method preferably has a metal-carbon and / or metal-nitrogen chemical bond, or a coordinate bond between the central metal atom and its ligand. Furthermore, a metal alkoxide having a metal-oxygen bond can also be used.

  Although metal halides can be used as the metal source chemical, it is difficult to remove halogen atoms from the substrate surface at low processing temperatures, so the metal source chemical should contain as little metal-halogen bond as possible. Is generally preferred. More preferably, the metal source chemical is not a metal halide.

  Furthermore, it is preferable that the raw chemical is thermally stable. That is, the metal source chemical preferably does not thermally decompose at the deposition temperature during the pulse time. Furthermore, the metal source chemical preferably has a sufficient vapor pressure (at least about 0.05 mbar) at the raw material temperature. The source temperature must be lower than the deposition temperature to prevent source chemicals from condensing uncontrolled on the substrate. Source chemical molecules are chemisorbed onto the substrate and no more than about one source chemical molecule monolayer remains on the surface, followed by the next source chemical pulse to reach the reaction chamber .

Examples of metal source chemicals are listed below according to their group numbers in the periodic table of elements. However, one of ordinary skill in the art will appreciate that similar chemicals and derivatives of the disclosed chemicals can be used in the deposition method without departing from the scope of the present invention. Accordingly, the present invention is not limited to the disclosed chemicals.
Source chemicals can be obtained, for example, from Sigma-Aldrich, USA.

Group IIA Preferred Group IIA metal compounds include magnesium (Mg) compounds, particularly magnesium cyclopentadienyl compounds such as bis (cyclopentadienyl) magnesium.

Group IIIB Group IIIB preferred metal compounds are scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), Including gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Cyclopentadienyl compounds such as tris (tetramethylcyclopentadienyl) lanthanum and silylamide compounds such as tris [N, N-bis (trimethylsilyl) amide] lanthanum (III) are particularly preferred.

Group IVB Preferred metal compounds of group IVB include titanium (Ti), zirconium (Zr), and hafnium (Hf) compounds. Particularly preferred are methylethylamides such as dialkylamides such as tetrakis (ethylmethylamido) hafnium (TEMAH), tetrakis (dimethylamido) hafnium (TDMAH), tetrakis (ethylmethylamino) zirconium, tetrakis (ethylmethylamino) titanium. Compounds (also referred to as dialkylamino compounds), cyclopentadienyl compounds such as trimethoxy (pentamethylcyclopentadienyl) titanium (TV), and alkoxide compounds such as titanium (IV) tert-butoxide.

Group VB Preferred metal compounds of Group VB include vanadium (V), niobium (Nb), and tantalum (Ta) compounds. Particularly preferred are dialkylamino compounds such as pentakis (dimethylamino) tantalum, imino compounds such as tris (diethylamino) (ethylimino) tantalum and tris (diethylamino) (tert-butylimino) tantalum, cyclopentadienyl compounds, bis (cyclo Silylamide compounds such as pentadienyl) N, N-bis (trimethylsilyl) amidovanadium and tris [N, N-bis (trimethylsilyl) amido] vanadium (III), β-diketonate compounds such as vanadium (III) acetylacetonate, An alkoxide compound such as vanadium (V) oxytriethoxide, niobium (V) ethoxide, or tantalum pentaethoxide.

Group VIB Preferred group VIB metal compounds include chromium (Cr), molybdenum (Mo), and tungsten (W) compounds. Particularly preferred are carbonyl compounds such as chromium hexacarbonyl Cr (CO) ₆ , tungsten hexacarbonyl W (CO) ₆ , molybdenum hexacarbonyl Mo (CO) ₆ , tricarbonyl (mesitylene) tungsten, bis (cyclopentadienyl) Cyclopentadienyl compounds such as tungsten dihydride, bis (cyclopentadienyl) ditungsten hexacarbonyl, bis (ethylcyclopentadienyl) chromium, and cyclopentadiene such as bis (isopropylcyclopentadienyl) tungsten dihydride It is an enyl derivative.

Group IIIA Preferred Group IIIA metal source compounds are aluminum (Al) compounds, especially monoalkylaluminum compounds L ¹ AlX ₂ , wherein X is selected from the group consisting of H, F, Cl, Br, I, RCHO , RCHO is an alkoxy group, L ¹ is a saturated or unsaturated linear or branched hydrocarbon, and a dialkylaluminum compound L ¹ L ² AlX (where X is H, F, Cl, Br, I, RCHO is selected from the group consisting of RCHO, RCHO is an alkoxy ligand, and L ¹ and L ² are straight or branched hydrocarbons having single, double, and / or triple bonds between carbon atoms) , Chokukusarima with trialkylaluminum compound ^L in 1 ^L 2 ^L 3 Al ^(wherein, L ¹ L 2 ^{L 3} is a single between carbon atoms, double, and / or triple bonds Comprises an organic aluminum compound containing at least one alkyl group bound to aluminum, such as a branched hydrocarbon).

The most preferred trimethylaluminum (CH ₃ ) ₃ Al, also known as TMA, is used as the aluminum source chemical.
It is preferable that the metal source compound is introduced into the reaction chamber as a gas and contacts the substrate surface.

Group VIA: Oxygen O source chemical It is preferable to use a strong oxidation source chemical containing oxygen. In a preferred embodiment, one or more oxygen source chemicals selected from the group of ozone, organic ozonides, oxygen atoms containing unpaired electrons, organic peroxides, and organic peracids are used.

Preferred peracids such as peracetic acid CH ₃ COOOH contain OOH and O groups bonded to the same carbon atom as shown in FIG.

Preferred organic ozonides contain both O and O—O between two carbon atoms, as shown in FIG.
Dimethyl peroxide and benzoyl peroxide are examples of suitable organic peroxides.

In addition, other preferred peroxides include those of formulas I and II.
R ¹ —O—O—R ² (I)
Wherein R ¹ and R ² are linear, branched, or cyclic organic ligands such as CH ₃ , (CH ₃ ) ₃ C, C ₆ H ₅ or benzoyl.
R ¹ —O—O—H (II)
(Wherein R ¹ is a linear, branched or cyclic organic ligand such as CH ₃ , (CH ₃ ) ₃ C, C ₆ H ₅ )

  Most preferably, ozone is used as the oxygen source. Water is preferably not used as a source chemical for the deposition process. The growth rate of aluminum oxide obtained from TMA and ozone can be about 0.8 kg / cycle. The surface reaction between ozone and trimethylaluminum, or the portion bound to the surface of trimethylaluminum, such as dimethylaluminum and monomethylaluminum, results in a self-saturated chemisorption reaction between the subsequently pulsed trimethylaluminum and the substrate surface. It is believed to provide sufficient OH groups on the aluminum oxide surface.

In addition to serving as an oxygen source for the method, ozone has a large amount of chemical energy that is released when molecules are destroyed.
O ₃ (g)-> 3/2 O ₂ (g)
ΔH _f ⁰ = −142.7 kJ / mol, and ΔG _f ⁰ = −163.2 kJ / mol (N. N. Greenwood and A. Earnshow, “Chemistry of the Elements”, Pergamon Press, Ltd., 1988, x. Non-patent document 1))

As a result, the splitting of ozone molecules can provide additional energy to the upper molecular layer on the surface, thus promoting certain surface reactions. Densification of the Al ₂ O ₃ surface can proceed by removing excess OH groups and forming Al—O—Al bridges, as shown in FIG.

  Also, when the organic peroxide OO bond breaks, the resulting RO fragment is highly reactive.

  Prior to introduction into the reaction chamber, ozone or other oxygen source is optionally diluted with an inert gas. For example, an oxygen gas, an inert gas such as nitrogen, or a noble gas such as argon can be used for this purpose.

  Examples of applications where metal oxide films prepared by this method are particularly suitable include organic light emitting diodes or displays (OLED), organic fluorescent displays (OEL), organic solar cells (OSC), organic layers and surface acoustic waves ( An integrated circuit having a SAW) filter. These applications generally require low deposition temperatures and / or are sensitive to moisture and / or oxygen.

  According to the first preferred embodiment of the present invention, the organic EL display is provided with a passivation layer by a preferred deposition method. A typical organic EL display is manufactured by placing an anode 12 on a substrate 11 (see FIG. 1), which is generally made of glass or similar material. The hole transport layer 13 is deposited on the anode 12, and the light emitting layer 14 is deposited on the hole transport layer 13. Further, a layer 15 capable of transporting electrons is deposited on the light emitting layer 14. All of these 13 to 15 layers preferably contain an organic material. The organic material can be a polymer or a low molecular weight molecule. A cathode 16 is then formed on the layer 15 capable of transporting electrons. The cathode 16 is preferably made from a metal such as aluminum, magnesium or calcium coated aluminum. These metals can easily form an oxide layer on the surface and adversely affect the interface between the metal and the organic layer. Accordingly, a passivation layer 17 is deposited on the surface of the structure obtained by the method. Note that “surface” refers to all possible surfaces. Therefore, it is preferable to passivate vertical surfaces as well.

  According to a second preferred embodiment of the present invention, the SAW filter is provided with a protective layer by a preferred deposition method. A typical SAW filter is shown in FIG. The filter generally includes a first acoustic absorber 21 and a second acoustic absorber 22 disposed on a voltage substrate of quartz, lithium niobate, or lithium tantalate. The input signal is guided to the input converter 23, and the output signal is collected from the output converter 24. The input converter 23 converts the electrical signal into a small acoustic wave, which is again converted into an electrical signal by the output converter 24. Usually, the structure is hermetically sealed. The present invention replaces the hermetic encapsulation with a thin protective layer deposited on the surface of the SAW structure by the described method. Therefore, a finished SAW product can be obtained using a cheaper encapsulation method for the protective structure.

  In each of the above embodiments, the metal oxide passivation layer is preferably about 5 nm to 1,000 nm thick, more preferably about 25 nm to 75 nm.

In some embodiments, the protective metal oxide layer comprises a single metal oxide such as Ta ₂ O ₅ , TiO ₂ , or a ternary metal oxide such as Al ₂ TiO ₅ . In other embodiments, the metal oxide layer comprises a metal oxide doped with a different metal or metal oxide. For example, the aluminum oxide layer or the titanium oxide layer can be doped with a different metal such as Ta. In other embodiments, the metal oxide layer is a nanolaminate structure comprising alternating metal oxide layers, such as aluminum oxide and titanium oxide, or aluminum oxide and tantalum oxide.

In other embodiments, the passivation layer is a solid solution comprising two or more metal oxides. For example, the metal oxide layer can include Ta _2x Nb _2-2x O ₅ or Ti _m Zr _1-m O ₂ .

Examples of ALD reactors that can perform low temperature processing include single wafer reactors, reactors with multiple wafers or other substrates in planar or vertical substrate holders, and batch processing reactors. For example, organic solar cells are preferably coated with a protective layer in a process in a batch processing reactor in order to keep manufacturing costs per substrate low.
The invention is further illustrated by the following non-limiting examples.

Deposition of Al ₂ O ₃ thin film using either water or ozone as oxygen source Case A: Deposition of Al ₂ O ₃ film with water as oxygen source Al ₂ O ₃ thin film is a fluid produced by ASM Microchemistry Oy of Finland Deposited in a formula ALD reactor, model F-120. Trimethylaluminum (CH ₃ ) ₃ Al, also known as TMA, was used as the aluminum source chemical. Purified water was used as the oxygen source chemical. Raw chemicals were introduced into the reactor from external raw materials.

  The substrate was placed in the reaction space and the reactor was evacuated by a mechanical vacuum pump. Next, the pressure in the reaction space was adjusted to a range of about 5 to 10 mbar with flowing nitrogen gas. The reaction space was then heated to the deposition temperature.

  Thin films were deposited at either 100 ° C or 300 ° C. The source chemicals were pulsed into the reaction space according to the principle of ALD, for example, the pulses were separated from each other by an inert gas, preventing the source chemicals from mixing in the gas phase of the reaction space. Only surface reaction occurred.

The pulse delivery cycle is as follows.
TMA pulse 0.5s
N ₂ purge 1.0s
H ₂ O pulse 0.4s
N ₂ purge 1.5s

The growth rate of Al ₂ O ₃ from TMA and H ₂ O was 0.8 Å / cycle at 300 ° C and 0.5 Å / cycle at 100 ° C. The refractive index was 1.64 for the grown film at 300 ° C. and 1.59 for the grown film at 100 ° C. The grown film at 100 ° C. leaked immediately by electrical measurement, and it was impossible to measure the exact value of capacitance or breakdown voltage. The density of the film did not seem to be very high. A summary of the properties is shown in Table 1 below.

Case B: Deposition Al ₂ O ₃ thin film of the _Al 2 _{O 3} film as an oxygen source by ozone, fluidized ALD reactor manufactured by the Finnish ASM Microchemistry Oy, was deposited in the model F-120. Trimethylaluminum (CH ₃ ) ₃ Al, also known as TMA, was used as the aluminum source chemical. Ozone prepared in the facility was used as the oxygen source chemical. Raw chemicals were introduced into the reactor from external raw materials.

  The substrate was placed in the reaction space and the reactor was evacuated by a mechanical vacuum pump. Next, the pressure in the reaction space was adjusted to a range of about 5 to 10 mbar with flowing nitrogen gas. The reaction space was then heated to the deposition temperature.

  Thin films were deposited at either 100 ° C or 300 ° C. The raw chemicals were pulse delivered to the reaction space as in Case A according to the ALD principle.

The pulse cycle is as follows.
TMA pulse 0.5s
N ₂ purge 1.0s
O ₃ pulse 4.0s
N ₂ purge 1.5s
A summary of the properties of the thin film obtained is shown in Table 1 below.

＊測定は電気的に非常に漏洩し易い薄膜のため実施できなかった。

* Measurement was not possible due to a thin film that is very susceptible to electrical leakage.

TOF-ERDA analysis of a film grown from TMA and ozone at 100 ° C. revealed that the film contained 6.0% carbon and 15.8% hydrogen.
A comparison of Case A and Case B shows that replacing water with ozone was beneficial for low temperature deposition methods.

The substrate having the deposited organic thin film of _Al 2 _{O 3} thin film on the organic layer using ozone as an oxygen source were supplied to the reaction space of the F-450 ALD reactor manufactured by the Finnish ASM Microchemistry Oy. The pressure in the reaction space was adjusted to about 5-10 mbar with a mechanical vacuum pump and flowing nitrogen gas with a nominal purity of 99.9999%. The temperature of the reaction space was then adjusted to about 110 ° C. TMA evaporated from external raw materials and ozone prepared in the facility were alternately introduced into the reaction space and led to the surface. The pulse delivery time was 1 s for TMA and 4 s for O ₃ . Source chemical pulse delivery was separated from each other with nitrogen gas. The purge time lasted 1.0-1.5 s after each source chemical pulse delivery. These pulse delivery cycles consisting of two source chemical pulse deliveries and two purge periods were repeated until a 50 nm aluminum oxide thin film was formed on the substrate. Deposition generally required about 600 pulse delivery cycles. The deposition method had no detrimental effect on the organic layer. Furthermore, the passivation structure was preserved in normal room air without compromising the function of the organic layer.

Deposition of HfO ₂ thin film on organic layer using ozone as oxygen source A substrate with an organic thin film was provided in the reaction space of a Pulsar® 2000 ALCVD ™ reactor manufactured by ASM America, Inc., USA . The pressure in the reaction space was adjusted to about 5-10 mbar with a mechanical vacuum pump and flowing nitrogen gas with a nominal purity of 99.9999%. The temperature of the reaction space was then adjusted to about 100 ° C. Tetrakis (dimethylamino) hafnium TDMAH evaporated from external raw materials and ozone prepared in the facility were alternately introduced into the reaction space and brought into contact with the surface. TDMAH with a purity of 99.99% can be purchased, for example, from Sigma-Aldrich, USA. The pulse delivery time was 1 s for TDMAH and 2 s for O ₃ . Source chemical pulse delivery was separated from each other with nitrogen gas. The reaction space was purged for 1.0-2.0 s after pulse delivery of each source chemical.

These pulse delivery cycles consisting of two source chemical pulse deliveries and two purge periods were repeated until a 30 nm hafnium dioxide (HfO ₂ ) thin film was formed on the substrate. The growth rate of the high-density HfO ₂ thin film was 1.1 Å / cycle, and the thickness nonuniformity (1 sigma) on the entire substrate was 2%. When tetrakis (dimethylamino) hafnium (TDMAH) was replaced with tetrakis (ethylmethylamino) hafnium (TEMAH) during the process, the deposition temperature could be reduced to about 50 ° C. This results in significant cost savings in both the deposition reactor structure and process operating costs.

Deposition of Al ₂ O ₃ / Ta ₂ O ₅ layered thin film on organic layer using ozone as oxygen source Substrate with organic thin film is provided in the reaction space of F-450 ALD reactor manufactured by ASM Microchemistry Oy in Finland did. The F-450 reactor is suitable for single substrate and small batch processing. The pressure in the reaction space was adjusted to about 5-10 mbar with a mechanical vacuum pump and flowing nitrogen gas with a nominal purity of 99.9999%. The temperature of the reaction space was then adjusted to about 90 ° C. TMA evaporated from external raw materials and ozone prepared in the facility were alternately introduced into the reaction space and brought into contact with the surface. The pulse delivery time was 1 s for TMA and 4 s for O ₃ . Source chemical pulse delivery was separated from each other by a purge step that provided nitrogen gas to the reaction space. The purge time lasted 1.0-1.5 s after the pulse delivery of each source chemical. A pulse delivery cycle consisting of two source chemical pulse delivery and two purge periods was repeated 480 times until a 40 nm aluminum oxide thin film was formed on the substrate.

Next, pentakis (dimethylamino) tantalum (PDMAT) evaporated from external raw materials and ozone prepared in the facility were alternately introduced into the reaction space and brought into contact with the surface. The pulse delivery time was 2.5 s for PDMAT and 3 s for O ₃ . Source chemical pulse delivery was separated from each other by purging with flowing nitrogen gas. The purge time lasted 1.0-1.5 s after the pulse delivery of each source chemical. A pulse delivery cycle consisting of two source chemical pulse delivery and two purge periods was repeated until approximately 10 nm of Ta ₂ O ₅ was formed on the Al ₂ O ₃ surface.

The deposition method had no detrimental effect on the organic layer. The passivation structure composed of layered Al ₂ O ₃ / Ta ₂ O ₅ was preserved in normal indoor air without impairing the function of the organic layer. Furthermore, the Ta ₂ O ₅ layer deposited on the Al ₂ O ₃ surface improved the durability of the passivation layer against corrosive solutions such as NaOH solution.

  While the foregoing invention has been described with reference to several preferred embodiments, other embodiments will be apparent to those skilled in the art from the standpoint of the disclosure herein. Furthermore, one embodiment is disclosed from the contents of an EL display, and another embodiment is disclosed from the contents of a SAW filter, although those skilled in the art will recognize a number of different to the principles disclosed herein. You will easily find the use of the content.

  Accordingly, the invention is not limited by the description of the preferred embodiment, but is only defined by reference to the claims.

It is a schematic diagram which shows the cross section of the organic electroluminescent display sealed with the passivation layer with respect to the surrounding gas atmosphere. It is a figure which shows the structure of a SAW (surface acoustic wave) filter. FIG. 2 shows a preferred peracid structure such as peracetic acid CH ₃ COOOH containing OOH and O groups bonded to the same carbon atom. FIG. 2 shows the structure of a preferred organic ozonide containing both O and O—O groups between two carbon atoms. FIG. 6 shows the formation of Al—O—Al bridges that can result in removal of excess OH groups and densification of the Al ₂ O ₃ surface.

Claims (26)

An atomic layer deposition (ALD) method for depositing a metal oxide thin film on a substrate in a reaction chamber comprising a plurality of cycles, each cycle comprising:
A process for supplying a first reactant gas containing a metal compound, a step of chemically adsorbed monomolecular layer of one metal compound on a substrate,
Supplying a gaseous second reactant containing an oxygen source other than water, wherein the second reactant converts a portion of the first reactant adsorbed on the substrate into a metal oxide; Including
The substrate is maintained at a temperature of less than 190 ° C .;
The metal compound contains Ta and the oxygen source is selected from the group consisting of ozone, organic ozonides, oxygen atoms with unpaired electrons, organic peroxides, and organic peracids;
Method.   The method of claim 1, wherein the metal compound is pentakis (dimethylamino) tantalum (PDMAT).   The method of claim 1, wherein the oxygen source is diluted with an inert gas. The oxygen source includes one or more organic peroxides of the formula R ¹ —O—O—R ² (IV), where R ¹ is a linear, branched, or cyclic organic ligand. A process according to claim 1, wherein R ² is hydrogen or a linear, branched or cyclic organic ligand.   The method of claim 1, wherein the substrate is maintained at a temperature of less than 150 ° C. during an ALD process.   The method of claim 1, wherein the substrate is maintained at a temperature of less than 125 ° C. during an ALD process.   The method of claim 1, wherein the substrate is maintained at a temperature of less than 100 ° C. during an ALD process.   The method of claim 1, wherein the cycle is repeated until the thickness of the metal oxide film is formed from about 5 to about 1000 nm.   The method of claim 1, wherein the substrate comprises an organic light emitting layer.   The method of claim 1, wherein the substrate comprises a surface acoustic filter.   The method of claim 1, wherein the substrate comprises an organic solar cell layer.   The method of claim 1, wherein the thin film is deposited on an organic thin film.   The method of claim 1, wherein the thin film is deposited on an aluminum oxide surface. An atomic layer deposition (ALD) method for depositing a thin film of metal oxide on a moisture sensitive substrate comprising a plurality of cycles, each cycle comprising:
Forming a monomolecular layer of one metal compound in a self-limiting reaction on the substrate,
Reacting a metal compound on the substrate with an oxygen source other than water to convert the metal reactant into a metal oxide,
The substrate is maintained at a temperature of less than 190 ° C. during the ALD process;
The metal compound contains Ta and the oxygen source is selected from the group consisting of ozone, organic ozonides, oxygen atoms with unpaired electrons, organic peroxides, and organic peracids;
Method.   15. The method of claim 14, wherein the metal compound is pentakis (dimethylamino) tantalum (PDMAT).   The method of claim 14, wherein the metal oxide is a ternary metal oxide.   The method of claim 14, wherein the metal oxide is doped with a metal different from the metal in the metal compound.   The method of claim 14, wherein the thin film protects the substrate from moisture.   The thin film is deposited on a previously deposited metal compound layer by a method selected from the group consisting of chemical vapor deposition (CVD), physical vapor deposition (PVD), and atomic layer deposition (ALD). The method of claim 14, wherein the method is deposited.   The method of claim 14, wherein the thin film is deposited on a dielectric layer.   The method of claim 14, wherein the dielectric layer comprises aluminum oxide. A method of depositing a metal oxide thin film on a substrate sensitive to an ambient atmosphere by an atomic layer deposition (ALD) method including a plurality of cycles, each cycle comprising:
Comprising contacting the substrate with the first reactant vapor phase containing metal compound, a step of adsorbing a monolayer of one of said metal compound on said substrate,
Removing excess first reactant and gaseous reaction by-products from the reaction space;
Supplying gaseous ozone to the reaction space, the step of converting the portion of the first reactant adsorbed on the substrate into a metal oxide;
Removing excess ozone and gaseous reaction by-products from the reaction space;
The substrate is maintained at a temperature below 190 ° C. during the ALD process;
The metal compound includes Ta;
Method.   24. The method of claim 22, wherein the thin film protects the substrate from the ambient atmosphere.   23. The method of claim 22, wherein the thin film is deposited on a dielectric layer.   The method of claim 22, wherein the thin film is deposited on an aluminum oxide layer.   23. The method of claim 22, wherein the thin film is deposited on an organic layer.

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