JP2008518104A - Method for depositing lead-containing oxide film - Google Patents

Abstract

A method for producing a lead-containing oxide thin film by atomic layer deposition, comprising the step of using an organometallic lead compound having an organic ligand bonded to a lead atom by a carbon-lead bond as a lead oxide raw material. For example, ALD growth using Ph ₄ Pb, O ₃ , Ti (O ⁱ Pr) ₄ and H ₂ O as precursors at 250 ° C. and 300 ° C. yields a stoichiometric PbTiO ₃ thin film with excellent uniformity. It can be deposited on a support.

Description

  The present invention relates generally to the field of microelectronics, and more particularly to a method for producing lead-containing oxide thin films by gas phase deposition, more particularly atomic layer deposition (ALD), and to lead-containing oxide thin films. .

The lead titanate (PT) family consists of a wide range of solid compounds such as PZT (lead zirconate titanate), PLT (lead lanthanum titanate) and PLZT (lead lanthanum zirconate titanate). The properties of lead titanate (PbTiO ₃ ) are improved by adding dopants such as lanthanum and zirconium, for example, ferroelectric memories, pyroelectric infrared sensors, piezoelectric applications, electro-optic elements, and metal-insulator-semiconductors. It can be used for specific thin film applications such as insulators in (MIS) and metal-insulator-metal (MIM) capacitors. Moreover, lead niobate (PbNbO _x ) such as magnesium lead niobate (PMN) and zinc lead niobate (PZN) has similar characteristics and has the same potential for use as lead titanate. . Properties such as dielectric constant can be increased by, for example, mixing lead magnesium niobate (PbMgNbO ₃ ) with lead titanate to form a PMN-PT material. Furthermore, the PMN-PT material can be mixed with barium titanate (BT) to form a PMN-PT-BT material.

Perovskite-type PPbTiO ₃ has a high Curie temperature of 490 ° C., a relatively low dielectric constant (compared to other lead titanate family compounds), and a large pyroelectric coefficient. The lead titanate thin film basically has the same physical properties as the bulk material, but has the property of low operating voltage and high switching speed in memory applications. This PbMgNbO ₃ + PbTiO ₃ (PMN-PT) material has a very high K value of about 22600. Also, the PbMgNbO ₃ material itself has a high K value of about 7000.

Thin films of the above materials such as PT, PZT, PMN, PMN-PT have been made by various chemical and physical methods. The most commonly used deposition methods are metal organic chemical vapor deposition (MOCVD) including types such as laser induced MOCVD, plasma induced MOCVD, and ion beam induced MOCVD. In addition to conventional CVD techniques, the so-called “modified MOCVD” method has been used to deposit a-axis and c-axis oriented thin films. In such a method, the vapor of the metal precursor is introduced into the reactor alternately with the oxygen source. Other chemical and physical deposition methods used to make PbTiO ₃ thin films include radio frequency magnetron sputtering, pulsed laser ablation, sol-gel method, spin coating method, chemical solution deposition method and hybrid chemical method.

  For practical use, the lead-containing oxide thin film must meet strict quality requirements. Therefore, the thin film should be free of defects and have a low surface roughness. The contact surface between the ferroelectric and the support is also important. A low deposition temperature is preferred to avoid unwanted interfacial reactions during the semiconductor process.

  Atomic layer deposition (originally called ALD- or “atomic layer epitaxy” and abbreviated ALE) is a well-known method for depositing high quality thin films on a support. The ALD method is based on a sequential self-saturated surface reaction, yielding a thin film having uniform physical properties including film thickness and low impurity content. Reference should be made to the following two publications:

  Dr. T. Suntola, the inventor of ALD technology, explains the principle of the ALD type manufacturing method as “Handbook of Crystal Growth 3, Thin Films and Epitaxy, Part B: Growth Mechanisms and Dynamics, Chapter 14,“ Atomic Layer Epitaxy ” ", Pp. 601-663, Elsevier Science BV 1994", the disclosure of which is hereby incorporated by reference.

  A wide range of ALD precursors and ALD-grown materials have been proposed by Prof. M. Ritala and Prof. M. Leskela in a recent review “Handbook of Thin Film Materials, Vol. 1: Deposition and Processing of Thin Films, Chapter 2. “Atomic Layer Deposition”, pp. 103-159, Academic Press 2002 ”.

  However, the ALD method cannot be applied to known methods for depositing lead-containing oxide thin films. Furthermore, lead-containing oxide thin films deposited by known methods do not provide devices with sufficient performance levels.

  It should also be noted that lead oxide exists in a variety of different forms as lead can assume a valence state of +2 or +4 with respect to the state of the art and the problems faced. Lead oxide also has a variety of different crystal forms. As a result, it is difficult to deposit a lead oxide thin film containing only one oxide having a specific crystal form. Previous studies have shown that lead oxide thin films deposited by metal organic chemical vapor deposition (MOCVD) contain both lead oxide and oxygen-rich types of lead dioxide.

  Accordingly, there is a need for a repeatable and controllable method for depositing uniform thin films containing lead oxide.

The object of the present invention is to eliminate the problems associated with known processes and to use lead-containing oxide thin films such as high performance lead titanate (PbTiO ₃ ) or lead magnesium niobate (PbMgNbO ₃ ) for use in thin film applications. It is to provide a novel method for producing the above.

  Another object is to provide a method for producing a lead-containing oxide thin film containing other components.

  These and other objectives, along with their advantages over known methods and products, are achieved by the present invention as described in the specification and claims.

  According to the present invention, an organic metal having an organic ligand in which a metal oxide containing binary lead oxide and ternary, quaternary and more complex lead oxide is bonded to the lead atom of the compound by a carbon-metal bond. It can be grown from lead precursors by ALD. Surprisingly, typical organometallic precursors in which the metal is bonded to an organic residue via an oxygen atom do not cause native ALD growth or ALD growth only in a narrow temperature range, And it has been found that the manufactured thin film exhibits a high level of impurities. On the other hand, the lead precursor of the present invention provides ALD growth in various (wide) temperature ranges, and the thin film has a very low concentration of residue from the ligand.

  The present invention also provides a method of forming a lead-containing multicomponent oxide thin film on a support in a reaction space by atomic layer deposition.

  More specifically, the method for producing a thin film according to the present invention is mainly characterized by what is indicated in the characterizing part of claim 1.

  The method for producing a multi-component lead oxide film is mainly characterized by what is presented in the characterizing part of claim 23.

The present invention provides many advantages. Therefore, a stoichiometric PbTiO ₃ film having excellent uniformity is pioneered at a support temperature of 250 ° C. and 300 ° C., for example, Ph ₄ Pb, O ₃ , Ti (O ⁱ Pr) ₄ and H ₂ O. It can be deposited on the support by ALD growth used as. Also, a stoichiometric PbMgNbO ₃ thin film with excellent uniformity can be obtained at a support temperature of 250 ° C. and 300 ° C., for example, Ph ₄ Pb, Mg (Cp) ₂ , Nb (OEt) ₅ and O ₃ and / or It can be deposited on a support by ALD growth using H ₂ O as a precursor. Using these precursors with the deposition temperature and pulse ratio kept constant, the thickness of the PbTiO ₃ film was found to be primarily dependent on the number of deposition cycles, suggesting the original ALD growth.

  As will become apparent from the following examples, the thin film produced according to the present invention generally contains only a small amount of hydrogen impurities and carbon impurities according to the time-of-flight elastic recoil detection method (TOF-ERDA).

The deposited lead titanate film is amorphous, but by annealing the amorphous film at a temperature above 500 ° C., for example 600 ° C. or higher, according to the method of the present invention, crystalline PbTiO ₃ A thin film can be obtained. By converting an amorphous thin film to a crystalline thin film, a higher dielectric constant can be obtained.

  The present invention will now be discussed more closely with the detailed description and examples.

  As is known in the art, there are various types of basic ALD methods, including PEALD (plasma excited ALD) using plasma as the activation reactant. Conventional ALD or thermal ALD does not use plasma, but the temperature of the support overcomes the energy barrier (activation energy) in the collision between the species chemisorbed on the surface and the reactant molecules in the gas phase. Reference is made to an ALD process that is sufficiently high to do so that, during each ALD pulse sequence, it grows on the support surface to the atomic (element) or molecular (compound) layer of the thin film. For the purposes of the present invention, ALD covers both PEALD and thermal ALD.

Definitions In the context of the present invention, an “ALD type method” generally refers to a method for producing a thin film on a support, in which a solid thin film is formed for each molecular layer by a self-saturation chemical reaction on a heated surface. means. In this method, a gaseous reactant, that is, a precursor is introduced into a reaction space of an ALD type reaction apparatus and brought into contact with a support located in a chamber to cause a surface reaction. The pressure and temperature of the reaction space are adjusted to a range that avoids physical adsorption of the precursor (ie, gas condensation) and thermal decomposition. As a result, only a maximum of one material monolayer (ie, atomic layer or molecular layer) is deposited at each pulse cycle at a time. The actual growth rate of the thin film is generally indicated as a soot / pulse cycle and depends, for example, on the number of surface sites that can react on the heated surface and the bulk of the chemisorbed molecules. The substance pulses are separated from each other by time, and between the substance pulses, the reaction space is purged with an inert gas (eg, nitrogen or argon) or evacuated to react with excess gaseous reactants. Since by-products are removed from the chamber, gas phase reactions between the precursors and undesirable by-product reactions are suppressed.

  In the text of this application, the “reaction space” generally means a reaction apparatus or reaction chamber that can be conditioned so that a thin film can be deposited.

  In the context of this application, an “ALD reactor” means that the reaction space is in fluid communication with an inert gas source and at least one, preferably at least two precursor sources capable of pulsing, That is, precursor vapor extruded from a precursor source can be introduced into the reaction space as a gas pulse, the reaction space is in fluid communication with a vacuum generator (eg, a vacuum pump), and the temperature of the reaction space And a reactor in which the pressure and the gas flow rate can be adjusted to a range in which a thin film can be grown by an ALD type process.

  In the text of this application, “rare earth” means group 3 of the periodic table (scandium Sc, yttrium Y, lanthanum La) and lanthanide series (cerium Ce, praseodymium Pr, neodymium Nd, samarium Sm, europium Eu, gadolinium Gd, Terbium Tb, dysprosium Dy, holmium Ho, erbium Er, thulium Tm, ytterbium Yb and lutetium Lu).

  “Raw material” and “precursor” are used interchangeably in this application, and are intended to be volatile or gaseous compounds that can be used as starting compounds for thin film metal oxides.

A “multicomponent oxide” film refers to a film comprising an oxide of at least two metal species, typically 2 to 4 metal species. Such films can include oxides such as Pb (Zr, Ti) O ₃ or Pb (Mg, Nb) O _3, but multicomponent oxidation including both Pb (Mg, Nb) O ₃ and PbTiO _3. It may be formed of two or more different oxides such as a physical thin film. The multi-component oxide thin film can also include three different oxides such as Pb (Mg, Nb) O ₃ , PbTiO ₃ and BaTiO ₃ .

Raw material
Lead Precursor According to the present invention, an organometallic lead precursor having an organic ligand bonded to a lead atom by a carbon-lead bond is used as a source material in the production of a thin film in an ALD reactor. Organometallic lead compounds have 2 or 4 alkyl ligands or ligands containing aromatic groups. In particular, organometallic lead compounds have the formula
L ¹ L ² L ³ L ⁴ Pb
Wherein each of L ¹ , L ² , L ³ and L ⁴ is independently a linear or branched C ₁ -C ₂₀ alkyl or alkenyl group; at least one hydrogen atom is fluorine Halogenated alkyl or alkenyl groups substituted with atoms, chlorine atoms, bromine atoms or iodine atoms; aryl groups, preferably carbocycles such as phenyl, tolyl, xylyl, benzyl, and alkylaryl groups including cyclic dienes A group, a halogenated carbocyclic group; and a heterocyclic group (limited to those bonded to a metal via a carbon atom).

  According to a preferred embodiment, the precursor comprises four organic ligands selected from the group of optionally substituted, linear, branched or cyclic alkyl or aryl groups. “Alkyl” represents, for example, an alkyl group selected from methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl and t-butyl. Within each ligand, and within different ligands, the alkyl groups may be the same or different. Reference is made to chlorinated alkyl and alkenyl groups above. It is also possible to use other substituents such as hydroxyl, carboxy, thio, silyl and amino groups.

  Specific examples of the novel precursor in the present invention are tetraphenyl lead and tetraethyl lead.

Turning now to the figures, FIG. 1 represents the structure diagram 100 and the shaded ball diagram 110 of the tetraphenyllead Ph ₄ Pb molecule. The molecule consists of lead atoms 102, carbon atoms 104 and hydrogen atoms 106. It can be seen that the central Pb atom 102 of the Ph ₄ Pb molecule is protected with a phenyl C ₆ H ₅ ligand, resulting in good thermal stability of the precursor. For example, by further modifying the phenyl ligand so that there is one or more alkyl groups attached to the carbocycle instead of one or more hydrogen atoms, the protective effect of the ligand on the central Pb atom is further improved. In addition, the thermal stability of the Pb precursor can be improved.

The second metal source material required for the second metal precursor ternary or higher metal oxide is a metal compound or a composite metal compound containing two or more metals. The metals are generally transition metals and main group metals according to the classification recommended by IUPAC in the Periodic Table of Elements, ie Group 1 (Li, Na, K, Rb, Cs); Group 2 (Mg, Ca, Sr, Ba); Group 3 (Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu); Group 4 (Ti, Zr, Hf); Group 5 (V, Nb, Ta); Group 6 (Cr, Mo, W); Group 7 (Mn, Re); Group 8 (Fe, Ru, Os); Group 9 (Co , Rh, Ir); Group 10 (Ni, Pd, Pt); Group 11 (Cu, Ag, Au); Group 12 (Zn, Cd, Hg); Group 13 (Al, Ga, In, Tl) ); Group 14 (Si, Ge, Sn); and / or volatile or gaseous compounds of elements of groups including group 15 (Sb, Bi) It is selected from.

Since the properties of each metal compound are different, the suitability of each metal compound for use in the method of the present invention must be considered. The properties of the compounds are described, for example, in “NN Greenwood and A. Earnshaw, Chemistry of the Elements , 1 ^st edition, Pergamon Press, 1986”.

  In general, suitable second metal source materials are halides, preferably fluorides, chlorides, bromides or iodides; organometallic compounds, preferably alkoxides (see titanium isopropoxide and niobium ethoxide in Example 1). An alkylamino; an alkyl derivative of cyclopentadienyl, cyclopentadienyl; a dithiocarbamate; an amidinate; a beta-ketoiminate; a beta-diketiminate; and a group comprising a beta-diketonate compound of the desired metal or metals It is preferable. Double metal precursors, ie molecules containing two metals in different stoichiometric ratios, can also be used. Examples of the double metal precursor include double metal alkoxides shown in Gelest's chemical catalog (edited by B. Arkles, Gelest, Inc. 1995, pp. 344-346).

Oxygen precursor oxygen source material is water; oxygen; hydrogen peroxide H ₂ O ₂ , aqueous solution of hydrogen peroxide; ozone O ₃ ; oxide of nitrogen containing NO ₂ , NO, N ₂ O; halide-oxygen compound Peracid-C (= O) -O-OH; alcohols such as methanol, ethanol, propanol and isopropanol; alkoxides; oxygen-containing radicals such as O ^* and HO ^* , where * indicates an unpaired electron; and It is preferably selected from the group comprising these mixtures. Ozone gas is often diluted with oxygen gas depending on the production method of ozone. The oxygen precursor vapor is optionally diluted with an inert gas.

The process reaction temperature of the process can vary depending on the evaporation temperature and pyrolysis temperature of the precursor. A typical width is represented at about 150-400 ° C, especially about 180-380 ° C. Based on the results obtained for crystallization, tetraphenyl lead at temperatures below 300 ° C., typically about 200-290 ° C., for example about 250 ° C., to achieve film crystallization at slightly higher annealing temperatures. It is particularly preferred to grow a lead titanate film from

  According to the present invention, a vapor phase pulse of vapor deposited organometallic lead compound mixed with inert carrier gas or vapor deposited organometallic lead compound not mixed with inert carrier gas is introduced into the ALD reactor, where In contact with a suitable support. Deposition may be performed under normal pressure, but this method is preferably performed under reduced pressure. The pressure in the reactor is typically 0.01 to 20 mbar, preferably 0.1 to 5 mbar.

  The temperature of the support must be low enough to keep the bonds between the thin film atoms intact and to prevent thermal decomposition of the gaseous reactants. On the other hand, the temperature of the support must be high enough to keep the source material in the gas phase, i.e. condensation of gaseous reactants must be avoided. Furthermore, the temperature must be high enough to provide activation energy for the surface reaction.

  Under these conditions, the amount of reactant bound to the surface will be determined by the surface. This phenomenon is called “self-saturation”.

  For further details on the implementation of a typical ALD method, reference is made to the above cited references and Example 1 shown below.

Various types of supports can be used. Examples include silicon, silica, coated silicon, germanium, silicon germanium alloys, copper metal; noble metals and platinum metals including silver, gold, platinum, palladium, rhodium, iridium and ruthenium; transition metal nitrides such as tantalum nitride Various nitrides such as TaN; various oxides such as platinum group metal oxides such as ruthenium dioxide RuO ₂ ; various carbides such as transition metal carbides such as tungsten carbide WC; transition metal nitride carbides such as tungsten carbonitride WN high K oxides which function as and interfacial layer, for example, the dielectric surface, such as _{Al 2 O 3;; x C} y is La ₂ O ₃ and the like as examples of or rare earth oxides.

  Similarly, a surface consisting of lead oxide or a metal oxide containing ternary, quaternary or more complex lead oxide may be used for further deposition of thin films containing the precious metal and platinum metal groups and the materials described in the previous paragraph. Can be used as a support surface for. The resulting multilayer sandwich structure is utilized, for example, in metal-insulator-metal (MIM) devices.

  Usually, the deposited thin film layer forms the support surface for the next thin film.

To convert the adsorbed (chemisorbed) lead precursor to lead oxide, the reactor is evacuated and / or purged with a purge gas containing an inert gas and then an oxygen source such as ozone O ₃ The next gas phase pulse of material is introduced into the reactor. The oxygen precursor vapor is optionally diluted with an inert gas.

  By reacting the lead precursor and oxygen source material alternately, a lead-containing oxide thin film can be deposited. Typically, growth rates of about 0.10-0.20 Å / cycle are achieved.

  To produce a multi-component oxide thin film, the second metal source material can be introduced under ALD conditions.

  In particular, multi-component oxide thin films include Pb oxides, and preferably Bi, Ca, Ba, Sr, Cu, Ti, Ta, Zr, Hf, V, Nb, Zn, Cr, W, Mo, Al, rare earths. It is preferred that it consists essentially of an oxide selected from (e.g. La) and / or Si oxide, and therefore the corresponding gas or volatile metal compound is used in the process of the invention. The second (third etc.) metal source material can be oxidized using the same or other oxygen source material for the lead precursor.

  Titanium, lanthanum and zirconium are of particular interest as source materials for the second and / or third and / or fourth metals in ternary and other multicomponent lead-containing oxides. Niobium, magnesium and zinc are of particular interest as source materials for the second and / or third and / or fourth metals in ternary and other multicomponent lead-containing oxides. Multicomponent Pb / Ti and Pb / Ti and La and / or Zr, or multicomponent Pb / Nb and Pb / Nb and Mg oxides are potentially valuable as high K dielectric materials.

  According to one preferred embodiment, the multi-component film is produced by supplying an ALD reactor with alternating pulses of various metal precursors (followed by the oxygen source pulses described above). This embodiment based on a “mixing cycle” will result in a ferroelectric phase after deposition. In general, the ratio of the cycle comprising the lead-containing precursor and the subsequent pulse of the corresponding oxygen source to the cycle consisting of the pulse of the second metal source and the subsequent oxygen source is about 50: 1 ... 1:50, Preferably it is about 40: 1 to 1:40, especially about 35: 1 ... 1: 1 (metal to metal based on moles).

Theoretically, a stoichiometric oxide ABO ₃ where A and B are two different metals can be obtained by sequentially pulsing two metal precursors and the corresponding oxygen source, and The growth rate of the ternary oxide can be predicted by summing the growth rates of the constituent oxides. In practice, however, both assumptions often break due to differences in precursor reactivity. The effect of interfacial chemistry usually causes a change in the relative growth rate that can be determined by comparing the observed film thickness with the theoretical thickness calculated from the growth rate of the binary oxide. According to the present invention, it has been found that the relative growth rate of PbTiO ₃ is dependent on the pulse rate of the precursor and the deposition temperature. Maximum relative growth rates are obtained at 250 ° C. and 300 ° C. by using respective Ti: Pb pulse ratios of 1:15 and 1:50, 155% at 250 ° C. and 190% at 300 ° C. there were.

Another preferred embodiment includes the steps of producing a multi-component film by depositing a thin layer of each metal oxide and annealing the thin layer at an elevated temperature to provide a crystalline phase. In this method, an amorphous structure is first obtained and the high dielectric material is oxygenated at temperatures above 500 ° C., especially above 700 ° C. in the presence of oxygen (such as in the presence of air). It is obtained by annealing in the presence of a containing compound (eg N ₂ O) or an inert gas (eg N ₂ or Ar).

Thus, a stoichiometric or lead-rich film deposited at 250 ° C. under a nitrogen or oxygen atmosphere for at least 1 minute, preferably 5-60 minutes, typically about 10 minutes, typically 600- When annealing at a temperature in the range of 900 ° C., a polycrystalline tetragonal perovskite PbTiO ₃ phase (JCPDS Card No 6-452) can be observed by XRD. A particularly preferred method of crystallizing PbTiO ₃ for use in lead-containing oxide thin films deposited at 250 ° C. is annealing in oxygen. Films annealed in oxygen are smooth and shiny even when annealed at 900 ° C. On the other hand, annealing in nitrogen is a preferred embodiment for use with films deposited at 300 ° C.

  In the above embodiment, when supplying the second and further metal precursors to the ALD reactor, a gas phase pulse of the oxygen source material is not necessary, but the purge gas pulse is changed from the metal precursor pulse to the oxygen precursor pulse. Are preferably fed to the ALD reactor after each metal precursor pulse.

  The novel oxide thin film material of the present invention can be widely applied in the semiconductor industry. In particular, a thin film of lead titanate is used in an insulator layer of a pyroelectric infrared sensor, an electro-optic element, and a metal-insulator-semiconductor (MIS) or metal-insulator-metal (MIM) memory cell structure. it can.

  The following non-limiting examples illustrate the invention.

Example 1
ALD Method for Lead Oxide Film FIG. 2 shows a process sequence for the deposition of a multimetal oxide (eg, PbTiO ₃ ) thin film. Throughout the history of ALD (ALE), nested pulse cycles have been used for ALD film growth control programs. The control program stored in the computer memory and executed by the CPU comprises a nested pulse cycle routine including a programmable global pulse cycle counter 234 and local pulse cycle counters 214 and 228. The global pulse cycle counter 234 manages the thickness of the entire predetermined thin film. Each of the local pulse cycle counters 214 and 228 manages a predetermined thickness of a sublayer forming the thin film, for example, a binary metal oxide.

The thin film may have sub-layers that have phases with different chemical compositions and crystallinity when compared with each other and can be clearly distinguished. This type of film is called a nanolaminate. Also, the deposited sublayers can be very thin and are thoroughly mixed in the order of molecular layers during the deposition process or subsequent annealing, and the film is a single, homogeneous ternary (e.g., PbTiO ₃ ), quaternary (eg Pb (Zr, Ti) O ₃ ) or more complex solid compounds.

  Generally, the ALD reaction chamber is preheated to the deposition temperature to increase the system throughput. One support is loaded 202 into the reaction space of a single wafer reactor, or multiple supports are loaded into the reaction space of a batch reactor. The pressure in the reaction space is adjusted by a vacuum generator, such as a vacuum pump or an incoming inert gas, to expose 204 one or more supports to the inert gas stream.

Each pulse cycle consists of four basic phases: precursor 1 pulse / purge / precursor 2 pulse / purge. In this example, a first pulse cycle causes a lead oxide layer to grow on the surface. A lead precursor vapor is pulsed 206 into the reaction space. The Pb precursor molecules chemisorb to the heated surface of the reaction space containing the support until available active surface sites are consumed and the chemisorption process self-terminates. Excess Pb precursor molecules and gaseous by-products generated by the surface reaction are removed from the reaction space during the purge stage 208. Next, the oxygen precursor is exposed 210 to the support. The oxygen precursor molecule reacts with the chemisorbed Pb precursor molecule, and the ligand bound to lead is removed or burned, and oxygen forms a chemical bond with the surface Pb. Excess oxygen precursor molecules and gaseous by-products such as CO ₂ and H ₂ O produced by the surface reaction are removed from the reaction space during the purge stage 212. In general, a surface reaction with an oxygen precursor leaves a hydroxyl (—OH) group on the surface. These —OH groups act as active sites for chemisorption of the gas phase molecules of the next metal precursor pulse. As a result, only one lead oxide molecular layer is formed on the support surface. The increase in film thickness per pulse cycle is generally much less than the molecular layer thickness of PbO due to the bulky ligand bound to the chemisorbed Pb precursor molecules. Thereafter, the control program checks 214 the pulse cycle counter. If the predetermined thickness of the PbO sublayer has not yet been reached for the specified number of pulse cycles, the first pulse cycle is repeated 216 as necessary. If the thickness of the PbO sublayer is sufficient, the control program proceeds 218 to the second pulse cycle.

In this example, the second pulse cycle is used to add a second metal, for example titanium Ti, to a growing thin film, for example lead titanate PbTiO ₃ in the form of a metal oxide, for example titanium dioxide TiO _2. The A second metal precursor is pulsed 220 into the reaction space. The second metal precursor molecules chemisorb to the surface of the support until the available active surface sites are consumed and the chemisorption process is self-terminated. Excess second metal precursor molecules and gaseous by-products generated by the surface reaction are removed from the reaction space during the purge stage 222. Next, the oxygen precursor is exposed 224 to the support. The oxygen precursor molecule reacts with the chemisorbed second metal precursor molecule, and the ligand bound to the second metal is removed or burned, and oxygen forms a chemical bond with the second metal atom on the surface. Excess oxygen precursor molecules and gaseous by-products such as CO ₂ and H ₂ O produced by the surface reaction are removed from the reaction space during the purge phase 226. As a result, only one molecular layer of the second metal oxide is formed on the support surface. The increase in thin film thickness per pulse cycle is generally significantly less than the molecular layer thickness of PbO due to the roughly bulky ligand bound to the chemisorbed second metal precursor molecule. Next, the control program checks 228 the local pulse cycle counter. If the predetermined thickness of the second metal oxide sublayer has not yet been reached for the specified number of pulse cycles, the second pulse cycle is repeated 230 as many times as necessary. If the thickness of the second metal oxide sublayer is sufficient, the control program proceeds to the global pulse cycle counter 234 to determine whether the total thickness of the thin film has reached the target value. If the film thickness is not sufficient, the first and second pulse cycles are repeated 236. If the film thickness is sufficient, process control ends the global pulse cycle loop 238 and subsequent processing of the support, eg, annealing, other thin film deposition or patterning steps, 240 is performed.

The growth rate of lead oxide is usually smaller than the growth rate of the second metal oxide. Therefore, the number of repeats in the first pulse cycle is generally greater than the number of repeats in the second pulse cycle. During the deposition of stoichiometric PbTiO ₃ , the ratio of the first pulse cycle (PbO growth) to the second pulse cycle (TiO ₂ growth) is 10: 1 ... 30: 1 depending on the deposition temperature and the choice of precursor. Preferably in the order of

It is possible to reverse the order of metal oxide deposition. In that case, the first pulse cycle is used for the deposition of a second metal oxide (eg TiO ₂ ) and the second pulse cycle is used for the deposition of lead oxide. When depositing stoichiometric PbTiO ₃ in reverse order, the ratio of the first pulse cycle (TiO ₂ growth) to the second pulse cycle (PbO growth) also depends on the choice of deposition temperature and precursor. This time, it is preferably in the order of 1:10 to 1:30.

Chemical example (Example 2)
Material and Method Film deposition was performed using a commercial flow F-120 atomic layer deposition reactor (ASM Microchemistry). The thin film deposition was studied at a temperature of 250 to 300 ° C., and the pressure in the reactor at that time was 2 to 3 mbar. Tetraphenyllead (Ph ₄ Pb, Aldrich Chem., 97%) and titanium isopropoxide (Ti (O ⁱ Pr) ₄ , Aldrich Chem., 97%) were used as metal precursors. The metal precursor was evaporated in the reactor from an open source boat maintained at 165 ° C. and 40 ° C., respectively. Nitrogen was used as a carrier gas and a purge gas, and reactants were alternately introduced into the reactor. Nitrogen (> 99.999%) was obtained from a nitrogen generator (Nitrox UHPN 3000-1). Ozone generated from oxygen (purity> 99.999%) using an ozone generator (Fischer model 502) and water vaporized in a cylinder kept at 30 ° C., respectively, Ph ₄ Pb and Ti (O ⁱ Pr) Used as ₄ oxygen source. The size of the Si (100) (Okmetic, Finland) support used was 5 × 10 cm ² .

First, the deposition method of the binary oxide was studied, and the growth parameters of the ternary oxide were determined. When the pulse times of the reactants used were 1.5 s and 0.6 s for Ph ₄ Pb and Ti (O ⁱ Pr) ₄ , uniform thin films were obtained. The pulse time of O ₃ was 2 s, and the pulse time of H ₂ O was 1 s. The purge period was between 1 and 2 s depending on the pulse time of the previous precursor.

When depositing ternary PbTiO ₃ thin films, the ratio of binary oxide layers was varied by changing the relative number of pulses of Ph ₄ Pb / O ₃ and Ti (O ⁱ Pr) ₄ / H ₂ O. . The hatched sign means that the pulses are sequentially changed according to the ALD method. After repeating the lead oxide cycle many times, the titanium oxide cycle was performed only once, and the film was deposited by repeating this cycle. In general, the lead oxide cycle number varied between 5 and 50. By changing the total number of PbO / TiO ₂ layers, the thickness of the entire film was controlled.

The thickness of the deposited PbTiO ₃ film was evaluated with a Hitachi U-2000 spectrometer using a wavelength range of 190-1100 nm. Pb and Ti contents were measured using a Philips PW 1480 X-ray fluorescence spectrometer equipped with an Rh X-ray tube.

  The amount of impurities was measured by time-of-flight elastic recoil detection (TOF-ERDA) on selected samples. TOF-ERDA measurements were made at the accelerator laboratory at the University of Helsinki.

The crystallinity and preferred orientation of the films were studied by X-ray diffraction (Philips MPD 1880) using Cu _Kα rays. The selected samples were annealed in an RTA oven (PEO 601, ATV Technologie GmbH, Germany) under N ₂ or O ₂ (> 99.999%) atmosphere at 500-900 ° C. for 10 minutes at atmospheric pressure. A heating rate of 20 ° C./min and a cooling rate of 25 ° C./min were used. The surface morphology of selected samples was analyzed with an atomic force microscope (AFM) AutoProbe CP (Park Scientific Instruments / Veeco) operating in intermittent-contact mode using Ultralevels ^™ (Veeco) silicon cantilevers. Roughness was calculated as a root mean square (rms) value.

Results The growth rate of the PbO thin film was found to be 0.13 Å / cycle at 250 ° C and 0.10 Å / cycle at 300 ° C when the Ph ₄ Pb pulse time was 1 to 1.5 s. In order to sufficiently saturate the surface, the pulse time of Ph ₄ Pb when depositing PbTiO ₃ was 1.5 s. The pulse time was 2 s for ozone, 0.6-0.8 s for titanium isopropoxide, and 1 s for water.

Since the growth rate of lead oxide is smaller than the growth rate of titanium dioxide, the deposition of PbTiO ₃ begins with the variable lead oxide cycle (Ph ₄ Pb / O ₃ ) followed by the titanium oxide cycle (Ti ( O ⁱ Pr) ₄ / H ₂ O) was performed once. It has been found that under conditions where the deposition temperature and pulse ratio are constant, the thickness of the PbTiO ₃ thin film is primarily dependent on the number of deposition cycles.

  From the XRF measurement, as shown in FIG. 6, it was found that the atomic ratio of Ti / Pb in the film depends on the relative amount of the titanium pulse. The XRF results were calibrated by plotting the XRF Ti / Pb ratio against the Ti / Pb ratio measured by RBS. The results were in harmony with each other. Stoichiometric films were obtained with a Ti: Pb pulse ratio of 1:10 at 250 ° C. and a Ti: Pb pulse ratio of 1:28 at 300 ° C.

  As a result of TOF-ERDA analysis, the level of impurities was low, impurities other than carbon and hydrogen were not detected, the carbon content was 0.2% or less, and the hydrogen content was 0.1 to 0.5%.

(Example 3)
Preparation of PbO ₂ Film by Ph ₄ Pb / O ₃ Method A lead oxide thin film was grown by ALD using tetraphenyl lead Ph ₄ Pb as a lead precursor. The evaporation temperature was 165-170 ° C. In the Ph ₄ Pb / O ₃ method, the influence of the deposition temperature on the growth rate was examined in the temperature range of 185 to 400 ° C. The pulse time of Ph ₄ Pb was 1.0 to 3.0 s. The ozone pulse was changed in the range of 1.0 to 3.0 s, and the nitrogen pulse was changed in the range of 1.0 to 2.5 s.

In the case of Ph ₄ Pb, the growth rate decreased with increasing deposition temperature. A constant growth rate of 0.13 kg / cycle was obtained at 200-250 ° C. The influence of the pulse time of Ph ₄ Pb was examined at 250 ° C. and 300 ° C. The growth rate at 300 ° C. was almost independent of the pulse time, with only a slight increase in growth rate from 0.13 to 0.16 liters / cycle at 250 ° C.

The film deposited by the Ph ₄ Pb / O ₃ method was polycrystalline and was orthorhombic (O) or tetragonal (T) lead dioxide (PbO ₂ ). When deposition was performed below 300 ° C., the strongest reflection was T (110). Above 300 ° C., the orientation changed and the strongest reflection was O (111).

  According to TOF-ERDA, the ratio of lead to oxygen approximated 0.7. The level of impurities in the film deposited at 250 ° C. was 0.5% for carbon and less than 0.1% for hydrogen.

The accompanying graph display of the results (FIGS. 3-7) is a graphical representation of the results of ALD growth of the lead oxide film.

FIG. 3 shows the growth rate of the PbO ₂ thin film as a function of the deposition temperature. Tetraphenyllead Ph ₄ Pb was used as the lead precursor and ozone O ₃ was used as the oxygen precursor. The pulse times of Ph ₄ Pb and O ₃ were 1.0 s and 2.0 s, respectively. When the temperature of the support was in the range of 200 to 250 ° C., a constant PbO ₂ growth rate was obtained. As a comparison, inset 300 shows the growth rate of PbO ₂ when Pb (thd) ₂ and O ₃ are used as precursors. The pulse times of Pb (thd) ₂ and O ₃ were 1.0 s and 1.5 s, respectively. The temperature of the support had a fairly strong influence on the growth rate of PbO ₂ .

FIG. 4 shows XRD patterns of a PbO ₂ film (a) deposited from Ph ₄ Pb at 250 ° C. and a PbO ₂ film (b) deposited from Pb (thd) ₂ at 150 ° C. The thickness of (a) was 70 nm, and the thickness of (b) was 170 nm. Diffraction peaks were identified based on JCPDS cards 25-447 and 37-517.

FIG. 5 shows the growth rate of lead oxide deposited at 250 ° C. and 300 ° C. with Ph ₄ Pb as the Pb precursor and with different pulse lengths of Ph ₄ Pb vapor. The pulse time of O ₃ was 2.0 s, and the purge time was 1.0 to 2.0 s depending on the pulse time of the precursor.

  FIG. 6 shows the abundance ratio of titanium and lead in a Pb—Ti—O film deposited on Si (100) at 250 ° C. and 300 ° C. as a function of the precursor pulse ratio. The composition of the membrane was measured by X-ray fluorescence (XRF) and independently verified by time-of-flight elastic recoil particle detection (TOF ERDA). A stoichiometric Pb—Ti oxide film is obtained when the weight ratio of Ti / Pb is 0.23, as indicated by the horizontal dashed line 602.

FIG. 7 shows an X-ray diffraction (XRD) pattern when a PbTiO ₃ film is annealed at 800 ° C. (a), 900 ° C. (b), and 1000 ° C. (c) for 10 minutes in a nitrogen N ₂ atmosphere.

Example 4
PbMgNbO ₃ film, PbMgNbO ₃ -PbTiO ₃ film and PbMgNbO ₃ -PbTiO ₃ -BaTiO ₃ a thin film including depositing lead magnesium niobate film, a lead precursor according to the invention, such as Pb ₄ Pb or Et ₄ Pb, Shikuropentaji Magnesium precursors such as enylmagnesium Mg (Cp) ₂ or Mg (thd) ₂ , niobium ethoxide Nb (OEt) ₅ or other alkoxides, niobium precursors such as niobium chloride NbCl ₅ or niobium fluoride NbF ₅ , and water Alternatively, it can be deposited by an oxygen precursor such as ozone.

  Mixing of lead titanate and / or barium titanate into lead magnesium niobate can be performed by adjusting the number of cycles of each subprocess. As an example, one cycle of lead magnesium niobate is deposited first, followed by one cycle of lead titanate. Furthermore, it is possible to deposit one cycle of barium titanate if necessary.

  There are multiple methods for depositing thin films containing magnesium lead. As an example, one generalized method for depositing niobium-containing lead oxide films is shown.

Subcycle 1 (PMN):
A lead precursor such as Ph ₄ Pb or Et ₄ Pb is introduced into the support in the reaction space. After introducing the lead precursor into the reaction space, the reaction space is purged with or without purge gas. After the purge step, a precursor containing water or oxygen such as ozone is introduced into the support in the reaction space. After the introduction of the precursor containing oxygen, the reaction space is purged with or without purge gas. After the purge step, a precursor containing niobium such as niobium ethoxide is introduced into the support in the reaction space. After introducing the niobium precursor into the reaction space, the reaction space is purged with or without purge gas. After the purge step, a precursor containing water or oxygen such as ozone is introduced into the support in the reaction space. After the introduction of the precursor containing oxygen, the reaction space is purged with or without purge gas. After the purge step, a precursor containing magnesium such as bis (cyclopentadienyl) magnesium or bis (2,2,6,6-tetramethyl-3,5-heptanedionate) magnesium is introduced into the support in the reaction space To do. After introducing the magnesium precursor into the reaction space, the reaction space is purged with or without purge gas. After the purge step, a single molecular layer of PbMgNbO ₃ is deposited on the support. This subcycle can be repeated as many times as necessary to form a film having the desired composition and / or structure. In this sub-cycle, the amount of metal deposited on the film can be adjusted by omitting one or more of the precursor pulse containing metal and the subsequent precursor pulse containing oxygen.

Subcycle 2 (PT):
A lead precursor such as Ph ₄ Pb or Et ₄ Pb is introduced into the support in the reaction space. After introducing the lead precursor into the reaction space, the reaction space is purged with or without purge gas. After the purge step, a precursor containing water or oxygen such as ozone is introduced into the support in the reaction space. After the introduction of the precursor containing oxygen, the reaction space is purged with or without purge gas. After the purge step, a titanium-containing precursor such as titanium methoxide or titanium isopropoxide is introduced into the support in the reaction space. After introducing the titanium precursor into the reaction space, the reaction space is purged with or without purge gas. After the purge step, a precursor containing water or oxygen such as ozone is introduced into the support in the reaction space. After the introduction of the precursor containing oxygen, the reaction space is purged with or without purge gas. After the purge step, a single molecular layer of PbTiO ₃ is deposited on the support. This sub-cycle can be repeated as many times as necessary to form a film of the desired composition and / or structure. In this sub-cycle, the amount of metal deposited on the film can be adjusted by omitting one or more of the precursor pulse containing metal and the subsequent precursor pulse containing oxygen.

Subcycle 3 (BT):
Introducing a barium precursor such as the THF adduct bis (pentamethylcyclopentadienyl) barium Ba (C ₅ (CH ₃ ) ₅ ) THF _X (where X is 0-2) into the support in the reaction space To do. After introducing the barium precursor into the reaction space, the reaction space is purged with or without purge gas. After the purge step, a precursor containing water or oxygen such as ozone is introduced into the support in the reaction space. After the introduction of the precursor containing oxygen, the reaction space is purged with or without purge gas. After the purge step, a titanium-containing precursor such as titanium methoxide or titanium isopropoxide is introduced into the support in the reaction space. After introducing the titanium precursor into the reaction space, the reaction space is purged with or without purge gas. After the purge step, a precursor containing water or oxygen such as ozone is introduced into the support in the reaction space. After the introduction of the precursor containing oxygen, the reaction space is purged with or without purge gas. After the purge step, a single molecular layer of BaTiO ₃ is deposited on the support. This sub-cycle can be repeated as many times as necessary to form a film of the desired composition and / or structure. In this sub-cycle, the amount of metal deposited on the film can be adjusted by omitting one or more of the precursor pulse containing metal and the subsequent precursor pulse containing oxygen.

  These three subcycles can be repeated as many times as necessary to form a film of the desired composition and / or structure. By omitting the desired number of subcycles, the number of subcycles can be adjusted to match the desired film composition / structure. In addition, the order of subcycles can be changed.

  Annealing at high temperature and in the desired atmosphere can be performed for crystallization after deposition of a thin film containing lead magnesium niobate.

(Comparative example)
Production of PbO ₂ film by Pb (thd) ₂ / O ₃ method For comparison, an organometallic compound in which a ligand is bonded to a metal atom through an oxygen-metal bond as a lead precursor under ALD conditions Was used to deposit a lead oxide film.

The evaporation temperature of bis (2,2,6,6-tetramethyl-3,5-heptanedionate) lead Pb (thd) ₂ was 110-115 ° C. The effect of deposition temperature on the growth rate was investigated in the temperature range of 150-300 ℃. In order to optimize the deposition method, the precursor pulse time and purge time were also investigated. The pulse time examined for Pd (thd) ₂ was 1.0 to 3.0 s. The ozone pulse was changed between 1.0 and 3.0 s, and the purged nitrogen pulse was changed in the range of 1.0 to 2.5 s.

In the case of Pb (thd) _2, the growth rate increased with increasing deposition temperature. A clear film thickness distribution and blackened film surface were observed at 250 ° C or higher. The growth rate of the Pb (thd) ₂ method was 1.0 to 1.5 kg / cycle at a temperature below 200 ° C., and the growth rate increased to 7.6 kg / cycle when the deposition temperature reached 300 ° C.

The pulse time of Pb (thd) ₂ was examined at 150 ° C. The film was smooth at a pulse time of 1.0 s, and no change was observed even when the pulse time was increased, suggesting ALD type growth. Therefore, the pulse of Pb (thd) ₂ was kept at 1.0 s, and the pulse of ozone was fixed between 1.0 and 3.0 s.

The thin films deposited from Pb (thd) ₂ were all crystalline regardless of volume temperature. Below 200 ° C., the film was polycrystalline and had an orthorhombic (O) phase and a tetragonal (T) phase. The strongest reflection at 150 ° C. was tetragonal (110), while at 200 ° C., the strongest reflection was orthorhombic (111).

  According to TOF-ERDA, the ratio of lead to oxygen approximated 0.7. The impurity level of the film deposited at 150 ° C. was 1.1% for carbon and 0.1% for hydrogen.

  The invention has been described herein with reference to specific embodiments and features, but without departing from the spirit of the invention, deposition conditions (eg, support temperature and deposition pressure), precursor selection and It will be appreciated by those skilled in the art that various changes can be made to the properties (eg, composition, crystallinity, and thickness) of the thin film. Therefore, the scope of the present invention should not be limited to the foregoing description. Rather, the scope of the invention should be determined on the basis of the claims recited herein and their equivalents.

A structure diagram of a tetraphenyl lead Ph ₄ Pb molecule and a shaded ball diagram are shown. Figure 2 illustrates an example process sequence used to deposit a multi-metal oxide thin film. The growth rate of the PbO ₂ thin film is shown as a function of the deposition temperature. FIG. 3 shows an X-ray diffraction diagram of a PbO ₂ thin film deposited from a selected Pb precursor. Figure ₅ shows the deposition rate of lead oxide thin films deposited from Ph ₄ Pb at different temperatures with different material pulse lengths. Figure 5 shows the effect of Ti / Pb precursor pulse ratio on titanium and lead content in Pb-Ti-O films deposited at selected temperatures. The effect of annealing of the PbTiO ₃ film as shown by the X-ray diffraction diagram is shown.

Explanation of symbols

100 Structure Diagram 102 Lead Atom 104 Carbon Atom 106 Hydrogen Atom 110 Shaded Ball Diagram

Claims (27)

  A method for producing a lead-containing oxide thin film by atomic layer deposition, comprising a step of using an organometallic lead compound having an organic ligand bonded to a lead atom by a carbon-lead bond as a lead oxide raw material.   2. The method of claim 1, comprising using an organometallic lead compound having 2 or 4 alkyl ligands or a ligand comprising an aromatic group. The organometallic lead compound has the following formula:
L ¹ L ² L ³ L ⁴ Pb
[Wherein L ¹ , L ² , L ³ and L ⁴ are each independently a linear or branched C _{1 to} C ₂₀ alkyl group or alkenyl group, preferably a methyl group or an ethyl group. N-propyl group, i-propyl group, n-butyl group, sec-butyl group, t-butyl group; an alkyl halide in which at least one hydrogen atom is replaced by a fluorine atom, a chlorine atom, a bromine atom or an iodine atom An aryl group, preferably a phenyl group, a tolyl group, a xylyl group, a benzyl group, an alkylaryl group or the like, a halogenated carbocyclic group; and a heterocyclic group] 3. A method according to claim 1 or 2, characterized in that   4. The method according to claim 1, comprising alternately supplying a gas phase pulse of an organometallic lead compound and at least one oxygen source material capable of forming an oxide with the source material into a reaction space. The method of crab.   The method according to claim 4, comprising producing a multicomponent oxide thin film.   The multi-component oxide thin film is bismuth oxide, calcium oxide, strontium oxide, copper oxide, titanium oxide, tantalum oxide, zirconium oxide, hafnium oxide, vanadium oxide, niobium oxide, chromium oxide, tungsten oxide, molybdenum oxide, aluminum oxide, 6. The method of claim 5, comprising a second metal oxide selected from the group of rare earth oxides and silicon oxides. The method according to claim 5 or 6, wherein the multi-component oxide thin film contains PbTiO ₃ or PbNbO ₃ .   The method of Claim 5 or 6 including the process of manufacturing a ternary oxide thin film.   9. A method according to any of claims 5 to 8, wherein the multi-component oxide thin film comprises at least one further metal oxide selected from the group of lanthanum oxide and zirconium oxide. The method of claim 9, wherein the multi-component oxide thin film comprises Pb (Zr, Ti) O ₃ or (Pb, La) (Zr, Ti) O ₃ .   11. A method according to any of claims 5 to 10, wherein the multi-component oxide thin film comprises at least one additional metal oxide selected from the group of magnesium oxide and zinc oxide. The method of claim 11, wherein the multi-component oxide thin film comprises Pb (Mg, Nb) O ₃ or Pb (Zn, Nb) O ₃ . The method of claim 11, wherein the multi-component oxide thin film comprises Pb (Mg, Nb) O ₃ and PbTiO ₃ . The method of claim 11, wherein the multi-component oxide thin film comprises Pb (Mg, Nb) O ₃ , PbTiO ₃ and BaTiO ₃ .   15. The method according to claim 1, wherein the lead oxide raw material contains tetraethyl lead or tetraphenyl lead.   The method according to claim 1, wherein the deposition temperature is about 150 to 400 ° C.   17. A method according to any of claims 5 to 16, wherein the second metal oxide is deposited from a source material selected from the group of halides or metal organic compounds.   18. The method of claim 17, wherein the source material is selected from the group of alkoxy compounds, alkylamino compounds, cyclopentadienyl compounds, dithiocarbamate compounds, and beta diketonate compounds.   The oxygen source material is water, oxygen, hydrogen peroxide, an aqueous solution of hydrogen peroxide, ozone, nitrogen oxide, halide-oxygen compound, peroxide (—C (═O) —OOH), alcohol, alkoxide. 19. The method according to any one of claims 1 to 18, wherein the method is selected from the group of oxygen-containing radicals and mixtures thereof. Since the PbTiO ₃ film is to obtain a PbTiO ₃ film of crystalline A method according to claim 7, characterized in that it is annealed at a temperature in excess of 500 ° C.. The method of claim 20, film of the PbTiO _3, characterized in that the annealing at temperatures above 800 ° C.. The method of claim 20 or 21 wherein the PbTiO ₃ film is characterized in that it is annealed in the presence of an inert atmosphere or oxygen. In forming a lead-containing multicomponent oxide thin film on a support in a reaction space by atomic layer deposition,
A gas phase pulse of a first metal source material, a second metal source material, and at least one oxygen source material capable of forming an oxide with the first metal source material and the second metal source material is formed in the reaction space. Including the step of alternately supplying
The first metal source material is an organometallic lead compound having an optionally substituted alkyl ligand or aryl ligand bonded to the lead atom of the organometallic lead compound by a carbon-lead bond,
The second metal source material is selected from Group 1, Group 2, Group 3, Group 4, Group 5, Group 6, Group 7, Group 7 (according to the classification recommended by IUPAC) in the periodic table of elements. Atom characterized in that it is a volatile compound of at least one transition metal or main group metal of Group 8, Group 9, Group 10, Group 11, Group 12, Group 13, and / or Group 14. A method for forming a lead-containing multicomponent oxide thin film on a support in a reaction space by layer deposition.   24. The method of claim 23, wherein the first metal source material is tetraethyl lead or tetraphenyl lead.   The method according to claim 23 or 24, wherein the oxygen source material is ozone or water.   26. The method according to any one of claims 23 to 25, comprising the step of producing a multi-component film by supplying alternating pulses of various metal precursors into the reaction space, followed by supplying pulses of oxygen source. The method described.   The ratio of the lead-containing precursor to the cycle consisting of the second metal source and the subsequent pulse of oxygen source and the cycle of the subsequent pulse of oxygen source corresponding to about 50: 1 ... 1:50 27. A method according to claim 26, characterized in that:

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