Method of manufacturing semiconductor device, substrate processing apparatus and non-transitory computer-readable recording medium

Provided is a technique of controlling a work function of a metal film. A composite metal nitride film is formed on a substrate present in a process chamber by alternately supplying a first source and a second source to the substrate, wherein the first source contains a first metal element, the second source contains an ethyl ligand and a second metal element that is different from the first metal element, and a bond between the second metal element and a nitrogen element in the composite metal nitride film has crystallinity.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 of Japanese Patent Application No. 2014-064064, filed on Mar. 26, 2014, in the Japanese Patent Office, the whole contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of manufacturing a semiconductor device, a substrate processing apparatus and a non-transitory computer-readable recording medium.

2. Description of the Related Art

Various types of metal films are used in transistor gate electrodes such as a metal-oxide-semiconductor field effect transistor (MOSFET) or capacitor electrodes of a dynamic random access memory (DRAM).

A gate stack structure in which a high-k film is formed on a substrate and a gate electrode is formed on the high-k film has been known as an example of a transistor structure. A metal nitride film, e.g., a titanium nitride (TiN) film, has been widely employed as a gate electrode (see, for example, Patent document 1).

RELATED ART DOCUMENT

Patent Document

SUMMARY OF THE INVENTION

A work function varies according to the desired performance of a device. For example, a metal film having a lower work function than that of a TiN film is required to decrease power consumption in an NMOS type transistor. As described above, a required work function varies according to the desired performance of a device and thus a work function of a metal film is required to be controlled.

It is a main object of the present invention to provide a technique of controlling a work function of a metal film.

According to one aspect of the present invention, there is provided a technique including (a) supplying a first metal source including a first metal element to a substrate accommodated in a process chamber and exhausting the first metal source from the process chamber; (b) supplying a second metal source including an ethyl ligand and a second metal element different from the first metal element to the substrate and exhausting the second metal source from the process chamber; and (c) supplying a reactive gas containing nitrogen to the substrate and exhausting the reactive gas containing nitrogen from the process chamber, wherein (a) through (c) are repeated a plurality of times to form a metal nitride film including the first metal element, a second metal element and nitrogen.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

First, a substrate processing apparatus employed in the present embodiment will be described. In detail, the substrate processing apparatus is a semiconductor device manufacturing apparatus and is used in a process of a semiconductor device manufacturing process.

In the following description, a case in which a single-wafer type substrate processing apparatus capable of forming a film on one substrate at a time is used as an example of a substrate processing apparatus will be described.

(1) Structure of Substrate Processing Apparatus

First, a schematic configuration diagram of a substrate processing apparatus employed in the present embodiment will be described below.

Process Chamber

As illustrated inFIG. 1, the substrate processing apparatus according to the present embodiment includes a process container102. The process container102is configured, for example, as a flat air-tight container that is round in a top view. The process container102is formed of, for example, a metal material such as aluminum (Al) or stainless steel (SUS), quartz (SiO2), etc. In the process container102, a process chamber101is formed. In the process chamber101, a wafer100, e.g., a silicon wafer, which serves as a substrate is processed.

Support

In the process container102, a support103is installed to support the wafer100. The support103is formed of for example, quartz (SiO2), carbon, ceramics, silicon carbide (SiC), aluminum oxide (Al2O3) or aluminum nitride (AlN). A susceptor117formed of, for example, quartz (SiO2), carbon, ceramics, silicon carbide (SiC), aluminum oxide (Al2O3) or aluminum nitride (AlN) is installed as a support table on a top surface of the support103. The wafer100is placed on the susceptor117. A heater106serving as a heating unit (heating source) for heating the wafer100is embedded in the support103. Also, a lower end portion (pillar) of the support103passes through a lower portion of the process container102.

Lifting Mechanism

A lifting mechanism107bconnected to the lower end portion of the support103is installed outside the process container102. By operating the lifting mechanism107b, the support103is moved up or down to move the wafer100supported on the susceptor117upward or downward. The support103(the susceptor117) is moved down to the height of a wafer transfer port150(which will be described below) so as to transfer the wafer100, and is moved up to a wafer processing position as illustrated inFIG. 1so as to process the wafer100. The vicinity of the lower end portion of the support103is covered with bellows103aand the inside of the process container102is maintained in an airtight state.

Lifter Pin

A plurality of lifter pins108b, e.g., three lifter pins108b, are installed on a lower surface (bottom surface) of the process container102. Through-holes108aare installed at locations on the support103(including the susceptor117) corresponding to the lifter pins108bto pass through the through-holes108a. When the support103is moved down to a wafer transfer position, top ends of the lifter pins108bprotrude from a top surface of the susceptor117via the through-holes108a, so that the wafer100may be supported from below by the lifter pins108b. Also, when the support103is moved up to the wafer processing position, the lifter pin108bis buried from the top surface of the susceptor117, so that the wafer100may be supported from below by the susceptor117. The lifter pins108bare directly in contact with the wafer100and are thus preferably formed of quartz, alumina, etc.

Wafer Transfer Port

The wafer transfer port150is installed on a side surface of an inner wall of the process container102to transfer the wafer100to the inside or outside of the process container102. A gate valve151installed at the wafer transfer port150. When the gate valve151is opened, the inside of the process container102and the inside of a transfer chamber (spare chamber)171are communicated with each other. The transfer chamber171is formed in a transfer container (airtight container)172and a transfer robot173is installed in the transfer chamber171to transfer the wafer100. The transfer robot173includes a transfer arm173ato support the wafer100when the wafer100is transferred. When the gate valve151is opened in a state in which the support103is moved down to the wafer transfer position, the wafer100may be transferred between the inside of the process chamber101and the inside of the transfer chamber171through the transfer robot173. The wafer100transferred into the process chamber101is temporarily placed on the lifter pin108bas described above. A load lock chamber (not shown) is installed at a side of the transfer container172opposite the side of the transfer container172at which the wafer transfer port150is installed. The wafer may be transferred between the inside of the load lock chamber and the inside of the transfer chamber171through the transfer robot173. The load lock chamber may also act as a spare chamber configured to temporarily accommodate a non-processed wafer100or a processed wafer100.

Exhaust System

An exhaust port160configured to exhaust an atmosphere in the process container102is installed at a side surface of an inner wall of the process container102opposite the wafer transfer port150. An exhaust pipe161is connected to the exhaust port160via an exhaust chamber160a. A pressure adjustment unit162such as an auto pressure controller (APC) which serves as a pressure control device for controlling a pressure in the process chamber101to have a predetermined pressure, a source collecting trap163and a vacuum pump164are sequentially connected in series to the exhaust pipe161. An exhaust system (exhaust line) mainly includes the exhaust port160, the exhaust pipe161and the pressure adjustment unit162. The source collecting trap163and the vacuum pump164are installed in a semiconductor manufacturing process in which the substrate processing apparatus is installed but may be installed in the substrate processing apparatus.

Gas Inlet

A gas inlet110is installed at an upper portion of the process container102[a top surface (ceiling wall) of a shower head140which will be described below] to supply various gases into the process container102. A gas supply system (which will be described below) is connected to the gas inlet110.

Shower Head

In the process container102, the shower head140is installed as a gas dispersion mechanism between the gas inlet110and the process chamber101. The shower head140includes a dispersion plate140athat disperses a gas introduced via the gas inlet110, and a shower plate140bthat more uniformly disperses the gas passing through the dispersion plate140ato be supplied to a surface of the wafer100on the support103. A plurality of air vents are installed in the dispersion plate140aand the shower plate140b. The dispersion plate140ais disposed to face the top surface of the shower head140and the shower plate140b. The shower plate140bis disposed to face the wafer100on the support103. A space is formed between the top surface of the shower head140and the dispersion plate140a, and a space is formed between the dispersion plate140aand the shower plate140b. These spaces act as a first buffer space140cconfigured to diffuse a as supplied via the gas inlet110and a second buffer space140dconfigured to diffuse a gas passing through the dispersion plate140a.

Exhaust Duct

A stepped portion101ais formed on a side surface of an inner wall of the process chamber101. The stepped portion101asupports a conductance plate104. The conductance plate104is a ring-shaped board having an inner circumferential portion with an opening for accommodating the wafer100. A plurality of outlets104aare arranged in an outer circumferential portion of the conductance plate104in a main direction at predetermined intervals.

In the process container102, a lower plate105is locked into an outer circumferential portion of the support103. The lower plate105includes a ring-shaped concave portion105band a flange portion105aformed integrally with an upper inner circumferential portion the concave portion105b. The concave portion105bis installed to block a gap between the outer circumferential portion of the support103and the side surface of the inner wall of the process chamber101. A plate exhaust port105cis installed on a part of a bottom portion of the concave portion105bnear the exhaust port160to discharge (circulate) a gas from the inside of the concave portion105bto the exhaust port160. The flange portion105afunctions as a lock unit to be locked into an upper peripheral portion of the support103. Since the flange portion105ais locked into the upper peripheral portion of the support103, the lower plate105is moved up or down with the support103when the support103is moved up or down.

When the support103is moved up to the wafer processing position, the conductance plate104blocks an upper opening of the concave portion105bof the lower plate105, and an exhaust duct159that uses the inside of the concave portion105bas a gas channel region is formed. Also, the conductance plate104and the lower plate105are preferably formed of a high-temperature retaining material, e.g., high-temperature resistant and high-load resistant quartz, considering a case in which a reactive product deposited on an inner wall of the exhaust duct159is etched (a case in which self-cleaning is performed).

The flow of a gas in the process chamber101when the wafer100is processed will now be described. First, a gas supplied into the shower head140via the gas inlet110flows into the second buffer space140dthrough an opening in the dispersion plate140avia the first buffer space140c, is supplied into the process chamber101through an opening in the shower plate140b, and is then uniformly supplied onto the wafer100. The gas supplied onto the wafer100radially flows outward. A residual gas that has been in contact with the wafer100radially flows outward on the exhaust duct159on the outer circumferential portion of the wafer100, i.e., on the conductance plate104, and is discharged into the gas channel region (the concave portion105b) included in the exhaust duct159via the outlets104aof the conductance plate104. Then, the gas flows in the exhaust duct159, flows through the plate exhaust port105c, and is then exhausted to the exhaust port160. By supplying a gas as described above, the gas may be suppressed from flowing back to the bottom of the process chamber101, i.e., a back surface of the support103or a bottom surface of the process chamber101.

Gas Supply System

Next, a structure of the gas supply system connected to the gas inlet110will be described with reference toFIG. 2.FIG. 2is a schematic configuration diagram of the gas supply system of the substrate processing apparatus ofFIG. 1.

Inert Gas Supply System

A mass flow controller (MFC)235aserving as a flow rate controller and a valve233aare sequentially installed at a gas supply pipe232afrom an upstream end. For example, nitrogen (N2) gas which is an inert gas is supplied to the gas inlet110via the gas supply pipe232a. A first inert gas supply system mainly includes the gas supply pipe232a, the MFC235aand the valve233a.

A MFC235gand a valve233gare sequentially installed at a gas supply pipe232gfrom the upstream end. For example, N2gas which is an inert gas is supplied into the gas inlet110via the gas supply pipe232g. A second inert, gas supply system mainly includes the gas supply pipe232g, the MFC235gand the valve233g.

An inert gas supply system includes one or both of the first inert, gas supply system and the second inert gas supply system. Also, the first and second inert gas supply systems may be separately used according to a manner of processing the wafer100.

Source Supply System

A vaporizer270dis installed at a gas supply pipe232d. A liquid source tank291d, a liquid mass flow controller (LMFC)295dserving as a liquid flow rate controller and a valve293dare sequentially installed at an upstream side of the vaporizer270dfrom the upstream end. A supply rate of a liquid source into the vaporizer270d(i.e. a supply flow rate of a gas vaporized in the vaporizer270dand supplied into the process chamber101) is controlled by the LMFC295d. A first source supply system mainly includes the gas supply pipe232d, the LMFC295dand the valve293d. The liquid source tank291dmay be further included in the first source supply system. Also, as will be described below; the first source supply system may act as a third source supply system.

A vaporizer270eis installed at a gas supply pipe232e. A liquid source tank291e, an LMFC295eand a valve293eare sequentially installed at an upstream side of the vaporizer270efrom the upstream end. A supply rate of a liquid source into the vaporizer270e(i.e., a supply flow rate of a gas vaporized in the vaporizer270eand supplied into the process chamber101) is controlled by the LMFC295e. A second source supply system mainly includes the gas supply pipe232e, the LMFC295eand the valve293e. The liquid source tank291emay be further included in the second source supply system.

An inert gas serving as a carrier gas is supplied into the vaporizer270dvia a gas supply pipe271d. An MFC273dand a valve272dare installed at the gas supply pipe271d. By diluting a vaporized gas generated by the vaporizer270dusing a carrier gas, the process uniformity of the wafer100such as film thickness uniformity within a plane of the wafer100placed on the susceptor117may be controlled. A first carrier gas supply system mainly includes the gas supply pipe271d, the MFC273dand the valve272d. For example, nitrogen (N2) gas is used as an inert gas. Also, a rare gas such as argon (Ar) gas, helium (He) gas, neon (Ne) gas, xenon (Xe) gas may be used as the inert gas.

An inert gas (N2gas) is supplied as a carrier gas into the vaporizer270evia a gas supply pipe271e. An MFC273eand a valve272eare installed at the gas supply pipe271e. By diluting a vaporized gas generated by the vaporizer270eusing a carrier gas, the process uniformity of the wafer100such as film thickness uniformity within a plane of the wafer100placed on the susceptor117may be controlled. A second carrier gas supply system mainly includes the gas supply pipe271e, the MFC273eand the valve272e.

A first source containing a metal element (first metal element) and a halogen element is supplied into the process chamber101through the gas supply pipe232dvia the LMFC295d, the vaporizer270d, a gas filter281d, etc. In the present embodiment, titanium (Ti) which is a transition metal element is selected as the metal element and chlorine (Cl) is selected as the halogen element. Here, titanium tetrachloride (TiCl4) is used as a source containing Ti and Cl. TiCl4is in a liquid state at room temperature and pressure. TiCl4that is in a liquid state is stored in the liquid source tank291d. Although Ti which is a transition metal element is used as the metal element here, the present invention is not limited thereto and the metal element may be selected from the transition metal group consisting of tungsten (W), tantalum (Ta), zirconium (Zr), hafnium (Hf), ruthenium (Ru), cobalt (Co) and nickel (Ni). For example, tungsten fluoride (WF5), tantalum chloride (TaCl5), zirconium chloride (ZrCl4), hafnium chloride (HfCl4), tungsten chloride (WCl6), etc. may be used as a source containing the transition metal element and the halogen element. Otherwise, a metal element other than a transition metal may be used. Also, the first source may be used as a third source as will be described below.

A source containing a metal element (second metal element) and an ethyl ligand is supplied into the process chamber101through the gas supply pipe232evia the LMFC295e, the vaporizer270e, a gas filter281e, etc. The second metal element is different from the first metal element. In the present embodiment, hafnium (Hf) which is a transition metal element is used as the second metal element. Here, tetrakis(diethylamino)hafnium (TDEAHf, Hf(N(C2H5)2)4) is used as a source containing Hf and an ethyl ligand. TDEAHf is in a liquid state at room temperature and pressure. TDEAHf that is in a liquid state is stored in the liquid source tank291e.

Although Hf which is a transition metal element is used as the second metal element here, the present invention is not limited thereto and the second metal element may be selected from the transition metal group consisting of tungsten (W), tantalum (Ta), zirconium (Zr), hafnium (Hf), ruthenium (Ru), cobalt (Co) and nickel (Ni). Otherwise, a metal element other than a transition metal may be used. However, a metal element that is different from the first metal element is selected and a source containing an ethyl ligand is used. For example, tetrakis(diethylamino)zirconium (Zr(N(C2H5)2)4, tris-diethylamino(tertiarybutylimino)tantalum (TBTDET), etc. may be used as a source containing the metal element and the ethyl ligand.

An MFC235band a valve233bare sequentially installed at a gas supply pipe232bfrom the upstream end. A reactive gas supply system mainly includes the gas supply pipe232b, the MFC235band the valve233b. A fourth source containing nitrogen is supplied into the process chamber101through the gas supply pipe232bvia the MFC235band the valve233b. Here, ammonia (NH3) is used as the fourth source containing nitrogen. However, the fourth source is not limited to NH3, and N2, nitrous oxide (NO), nitrogen oxide (N2O), etc. may be used.

Control Unit

As illustrated inFIG. 1, the substrate processing apparatus includes a controller300as a control unit.FIG. 3illustrates a case in which a control unit according to the present embodiment and various components are connected. The controller300which is a control unit (control means) is configured as a computer including a central processing unit (CPU)380a, a random access memory (RAM)380ba memory device380cand an input/output (I/O) port380d. The RAM380b, the memory device380cand the I/O port380dare configured to exchange data with the CPU380avia an internal bus380e. An input device382, e.g. a touch panel, which serves as a man machine interface (MMI) or a display device (display)372are connected to the controller300.

For example, the memory device380cincludes a flash memory, a hard disk drive (HDD), etc. In the memory device380e, a control program for controlling an operation of the substrate processing apparatus, a process recipe including an order or conditions of substrate processing which will be described below are stored to be readable. The process recipe is a combination of sequences of a substrate processing process which will be described below to obtain a desired result when the sequences are performed by the controller300, and acts as a program. Hereinafter, the process recipe, the control program, etc. will also be referred to together simply as a “program.” When the term “program” is used in the present disclosure, it should be understood as including only the process recipe, only the control program or both of the process recipe and the control program. The RAM380bis configured as a memory area (work area) in which a program or data read by the CPU380ais temporarily stored.

The I/O port380dis connected to the heater106, the lifting mechanism107b, the gate valve151, the transfer robot173, the pressure adjustment unit162, the vacuum pump164, the source collecting trap163, the MFCs235a,235b,235g,273dand273e, the valves233a,231d,233e,233g,293d,293e,272dand272e, the vaporizers270dand270e, the LMFCs295dand295e, the liquid source tanks291dand291e, etc.

The CPU380ais configured to read a process recipe from the memory device380caccording to a manipulation command, etc. which is input via the input device382while reading and executing a control program stored in the memory device380c. Also, based on the read control program and process recipe, the CPU380ais configured to control the flow rates of various gases using the MFCs235a,235b,235g,273dand273e; control the flow rate of a liquid source using the LMFCs295dand295e; control opening/closing of the valves233a,233d,233e,233g,293d,293e,272dand272e; control pressure adjustment using the pressure adjustment unit162; control temperature adjustment using the heater106; control driving and stopping of the vacuum pump164;

control upward/downward movement of the support103using the lifting mechanism107b, etc.

The controller300is not limited to a dedicated computer and may be configured as a general-purpose computer. For example, the controller300according to the present embodiment may be configured by preparing an external memory device383storing the above-described program, e.g., a magnetic tape, a magnetic disk (e.g., a flexible disk, a hard disk, etc.), an optical disc (e.g., a compact disc (CD), a digital versatile disc (DVD), etc.), a magneto-optical (MO) disc or a semiconductor memory (e.g., a Universal Serial Bus (USB) memory, a memory card, etc.), and then installing the program in a general-purpose computer using the external memory device383. Also, a means for supplying the program to a computer is not limited to using the external memory device383. For example, the program may be supplied to a computer using a communication means, e.g., the Internet or an exclusive line, without using the external memory device383. The memory device380cor the external memory device383may be configured as a non-transitory computer-readable recording medium. Hereinafter, the memory device380cand the external memory device383may also be referred to together simply as a “recording medium.” When the term “recording medium” is used in the present disclosure, it may be understood as only the memory device380c, only the external memory device383or both of the memory device380cand the external memory device383.

Structure of Semiconductor Device

Next, a structure of a gate of a transistor (semiconductor device) formed using the substrate processing apparatus described above will be described below. Here, an NMOS type transistor will be described as an example.

FIG. 4illustrate an example transistor gate formed using the substrate processing apparatus described above. In detail,FIG. 4illustrates a structure of an NMOS type transistor gate. As illustrated inFIG. 4, a gate has a stack structure in which a silicon-based insulating film formed on a silicon (Si) substrate using silicon oxide (SiO2), a high-k film formed on the silicon-based insulating film using hafnium oxide (HfO2) and a gate electrode formed on the high-k film using a composite metal nitride film (TiHfN) are stacked. Also, a capping film is formed on the TiHfN gate using a metal nitride film (TiN). An aluminum (Al) film is formed on a back surface of the silicon substrate.

Process of Manufacturing Gate of Semiconductor Device

Next, an example of a process of manufacturing a transistor gate illustrated inFIG. 4will be described.FIG. 5is a flowchart of an example of a process of manufacturing the transistor gate ofFIG. 4.

First, a sacrificial oxide film is removed from a silicon substrate by processing the silicon substrate, for example, with a 1% HF aqueous solution (‘HF treatment’ process). Then, a silicon oxide (SiO2) film is formed on a surface of the silicon substrate by thermal oxidation (‘SiO2formation’ process). The SiO2film is formed as an interface layer at an interface between the silicon substrate and a hafnium oxide (HfO2) film which will be formed thereafter.

Next, the HfO2film is formed as a high-k film on the SiO2film (‘High-k formation’ process). A gate insulating film includes the SiO2film and the HfO2film. Next, a composite metal nitride film is formed as a gate electrode on the HfO2film (‘N-side WFM deposition’ process). In the present embodiment, a titanium hafnium nitride film (TiHfN) is formed as the composite metal nitride film. As illustrated inFIG. 5, the first source (TiCl4) and the second source (TDEAHf) are alternately supplied in X cycles in this process.

Then, a titanium nitride film (TiN) is formed in-situ as a capping layer on the TiHfN film (‘in-situ cap TiN deposition’ process). Also, the titanium nitride film (TiN) is formed by, for example, physical vapor deposition (PVD) (‘TiN deposition’ process). Then, patterning is performed on the TiN film using a resist as a mask by photolithography (‘gate patterning’ process) and pattern etching is performed by dry etching (‘gate etching’ process). Then, the resist is removed (‘resist remove’ process). Then, forming gas annealing (FGA) such as hydrogen gas annealing is performed (‘FGA’ process). Thereafter, an aluminum layer is formed on a back surface of the silicon substrate (‘backside Al deposition’ process).

Processes of Forming TiHfN Film and TiN Film

Next, a process of forming the composite metal nitride film (TiHfN) of the gate electrode described above and a process of forming the metal nitride film (TiN film) of the capping layer will be described below. These processes are performed in the process chamber101of the substrate processing apparatus described above.

FIG. 6is a flowchart of an example of the process of forming the composite metal nitride (TiHfN) film and the process of forming the metal nitride (TiN) film, which are included in the flowchart ofFIG. 5.FIG. 7illustrates gas supply timing in the processes ofFIG. 6. In the following description, operations of various components of the substrate processing apparatus are controlled by the controller300.

When the term ‘wafer’ is used in the present disclosure, it should be understood as either the wafer itself, or both the wafer and a stacked structure (assembly) including a layer/film formed on the wafer (i.e., the wafer and the layer/fifth formed thereon may also be referred to collectively as the ‘wafer’). Also, when the expression ‘surface of the wafer’ is used in the present disclosure, it should be understood as either a surface (exposed surface) of the wafer itself or a surface of a layer/film formed on the wafer, i.e., an uppermost surface of the wafer as a stacked structure.

Thus, in the present disclosure, the expression ‘specific gas is supplied onto a wafer’ should be understood to mean that the specific gas is directly supplied onto a surface (exposed surface) of the wafer or that the specific gas is supplied onto a layer/film on the wafer, i.e., the uppermost surface of the wafer as a stacked structure. Also, in the present disclosure, the expression ‘layer or film is formed on a wafer’ should be understood to mean that the layer or film is directly formed on a surface (exposed surface) of the wafer or that the layer or film is formed on a layer or film formed on the wafer, i.e., the uppermost surface of the wafer as a stacked structure.

In the present disclosure, the term ‘substrate’ has the same meaning as the term ‘wafer,’ Thus, the term ‘wafer’ may be used interchangeably with the term ‘substrate.’

Substrate Loading Process (S101)

First, the gate valve151installed on the wafer transfer port150is opened to transfer the wafer100from the transfer chamber171into the process container102using the transfer robot173. The high-k film (HfO2) described above is formed on the wafer100. In addition to HfO2, the high-k film may include at least one film selected from the group consisting of aluminum oxide (AlO), zirconium oxide (ZrO), lanthanum oxide (LaO), yttrium oxide (YO), tantalum oxide (TaO), cerium oxide (CeO), titanium oxide (TiO), strontium titanium oxide (STO) and barium titanium oxide (BTO). The high-k film may further include not only the at least one film but also silicon oxide (SiO) or silicon nitride (SiN).

Substrate Placing Process (S102)

The wafer100transferred into the process container102is placed on the lifter pins108b. Then, the support103is moved up to the wafer processing position, so that the wafer100may be placed on the susceptor117.

Pressure Control Process (S103)

After the wafer100is placed on the susceptor117, the gate valve151is closed and the inside of the process chamber101is vacuum-exhausted by the vacuum pump164to have a desired pressure (degree of vacuum). In this case, the pressure in the process chamber101is measured by a pressure sensor (not shown) and is feedback controlled to the APC valve162.

Temperature Control Process (S104)

Also, the wafer100placed on the susceptor117is heated to a predetermined temperature by the heater106embedded in the support103. In this case, the amount of electric power supplied to the heater106is feedback controlled based on temperature information sensed by a temperature sensor (not shown), so that the wafer100may have a predetermined temperature distribution.

The pressure control and the temperature control described above are continuously performed until a first film-forming process and a second film-forming process which will be described below end.

Next, the first film-forming process of forming a TiHfN film which is a composite metal nitride film is performed by alternately supplying TiCl4and TDEAHf to the wafer100. In the first film-forming process, the following four steps are sequentially performed.

In step S105, TiCl4(first source) is supplied into the process chamber101. In detail, the valve293dof the gas supply pipe232dis opened to supply TiCl4to the vaporizer270d. In this case, the flow rate of the TiCl4supplied to the vaporizer270dis controlled by the LMFC295d. At the same time, the valve272dof the gas supply pipe271dis opened to supply N2gas to the vaporizer270d. The flow rate of the N2gas supplied to the vaporizer270dis controlled by the MFC273d. TiCl4gas vaporized by the vaporizer270dis supplied into the process chamber101with the N2gas supplied as a carrier gas to the vaporizer270dvia the gas filter281dand the gas inlet110. In this process, the valve233amay be opened to supply N2gas via the gas supply pipe232a(first inert gas supply system). Also, the valve233gmay be opened to supply N2gas via the gas supply pipe232g(second inert gas supply system).

In this process, the APC valve162is appropriately controlled to adjust a pressure in the process chamber101to be, for example, in a range of 20 Pa to 1,330 Pa. The supply flow rate of the TiCl4gas controlled by the LMFC295dis set to be, for example, in a range of 10 ccm to 100 ccm. Also, the flow rate of the N2gas supplied together with the supply of the TiCl4gas is set to be, for example, in a range of 0 ccm to 200 ccm. A time duration of exposing the wafer100to the TiCl4gas, i.e., a gas supply time (irradiation time), is set to be, for example, in a range of 0.01 to 300 seconds. In this case, the temperature of the heater106is set such that the temperature (process temperature) of the wafer100is, for example, in a range of 300° C. to 350° C., and preferably, a range of 330° C. to 350° C. When the TiCl4gas is supplied, a Ti-containing layer is formed on the wafer100to, for example, a thickness of less than one atomic layer to several atomic layers.

In step S106, the valve233dis closed to stop the supply of the TiCl4gas into the process chamber101. In this case, the inside of the process chamber101is vacuum-exhausted by the vacuum pump164while the APC valve162is open to remove the TiCl4gas (that did no react or that has contributed to the formation of the Si-containing layer) remaining in the process chamber101from the process chamber101. Also, in this case, N2gas is supplied into the process chamber101by opening the valve233aor233g(or while the valve233aor233gis open). The N2gas may act as a purge gas and greatly increase an effect of removing the TiCl4gas (that did not react or that has contributed to the formation of the Ti-containing layer) from the process chamber101. Purging is performed by supplying N2gas, for example, in a flow rate of 200 ccm for 1 to 60 seconds.

In this case, gases remaining in the process chamber101may not be completely removed and the inside of the process chamber101may not be completely purged. When a small amount of gases remains in the process chamber101, a subsequent step S107will not be negatively influenced by the gases. Also, the flow rate of the N2gas to be supplied into the process chamber101need not be high. For example, the inside of the process chamber101may be purged without causing step S107to be negatively influenced by the gases by supplying an amount of the N2gas corresponding to the capacity of the process chamber101. When the inside of the process chamber101is not completely purged, a purge time may be reduced to improve the throughput. Furthermore, the consumption of the N2gas may be reduced to a necessary minimum level.

In step S107, TDEAHf (second source) is supplied into the process chamber101. In detail, the valve293eof the gas supply pipe232eis opened to supply TDEAHf into the vaporizer270e. In this case, the flow rate of the TDEAHf supplied into the vaporizer270eis controlled by the LMFC295e. At the same time, the valve272eof the gas supply pipe271eis opened to supply N2gas into the vaporizer270e. The flow rate of the N2gas supplied into the vaporizer270eis controlled by the MFC273e. The TDEAHf gas vaporized by the vaporizer270eis supplied into the process chamber101with the N2gas supplied as a carrier gas to the vaporizer270evia the gas filter281eand the gas inlet110. In this process, the valve233amay be opened to supply N2gas via the gas supply pipe232a, similar to step S105. Also, the valve233gmay be opened to supply N2gas via the gas supply pipe232g.

In this case, the APC valve162is appropriately controlled to set a pressure in the process chamber101to be in, for example, a range of 20 Pa to 1,330 Pa. The supply flow late of the TDEAHf gas controlled by the LMFC295eis set to be in, for example, a range of 10 ccm to 100 ccm. Also, the flow rate of the N2gas supplied together with the TDEAHf gas is set to be in, for example, a range of 0 ccm to 200 ccm. A time duration of exposing the wafer100to the TDEAHf gas, i e. a gas supply time (irradiation time) is set to be in, for example, a range of 0.01 to 300 seconds. In this case, the temperature of the heater106is set such that the temperature of the wafer100is in, for example, a range of 300° C. to 400° C., preferably, a range of 330° C. to 400° C., and more preferably, a range of 330° C. to 350° C. When the temperature of the wafer100exceeds 400° C., the TDEAHf gas is pyrolized and thus a film-forming rate increases and controllability decreases. Thus, an upper temperature limit of the wafer100is preferably set to be in the range described above. The TDEAHf gas supplied into the process chamber101reacts with at least a portion of the Ti-containing layer formed on the wafer100in step S105. Thus, a TiHfN layer containing Ti, Hf and N is formed. In detail, Cl (halogen element) contained in the Ti-containing layer reacts with ethyl which is a ligand of amine contained in the TDEAHf gas and is thus removed from the Ti-containing layer. At the same time, the Ti-containing layer from which Cl is removed is combined with Hf and N contained in the TDEAHf gas to form a TiHfN layer.

In step S108, the valve233eis closed to stop the supply of the TDEAHf gas into the process chamber101. In this case, the inside of the process chamber101is vacuum-exhausted by the vacuum pump164while the APC valve162is open to remove the TDEAHf gas (that did not react or that has contributed to the formation of an HfN-containing layer) remaining in the process chamber101from the process chamber101. In this case, N2gas is continuously supplied into the process chamber101by opening the valve233aor233g(or while the valve233aor233gis open). The N2gas may act as a purge gas and greatly increase an effect of removing the TDEAHf gas (that did not react or that has contributed to the formation of the HfN-containing layer) from the process chamber101. Purging is performed by supplying gas, for example, in a flow rate of 200 ccm for 1 to 60 seconds.

In this case, similar to step S106, gases remaining in the process chamber101may not be completely removed and the inside of the process chamber101may not be completely purged.

One cycle including steps S105to S108described above is performed at least once (step S109). Thus, a composite metal nitride film containing titanium, hafnium and nitrogen, i.e., a TiHfN film, is formed. The above cycle is preferably repeatedly performed a plurality of times. Thus, the TiHfN film is formed on the high-k film on the wafer100to a predetermined thickness. Although the TiCl4gas is supplied prior to the supply of the TDEAHf gas in the present embodiment, the TDEAHf gas may be supplied prior to the supply of the TiCl4gas.

After the TiHfN film is formed, N2gas is supplied into the process chamber101by opening the valve233aof the inert gas supply pipe232aor the valve233gof the inert gas supply pipe232g(or while the valve233aor233gis open). The N2gas acts as a purge gas and purges the inside of the process chamber101to remove a gas remaining in the process chamber101from the process chamber101. Then, a second film-forming process is performed to form a TiN film as a capping layer on the TiHfN film. The second film-forming process is performed in the process chamber101after the first film-forming process is performed.

In step S205, TiCl4(third source) is supplied into the process chamber101. The process of supplying the TiCl4(including opening/closing valves, etc.) is the same as that in step S105described above and is not redundantly described here.

In this case, the APC valve162is appropriately controlled to set a pressure in the process chamber101to be in, for example, a range of 20 Pa to 1,330 Pa. The supply flow rate of the TiCl4gas controlled by the LMFC295dis set to be in, for example, a range of 10 ccm to 100 ccm. Also, the flow rate of an inert gas such as N2gas supplied together with the TiCl4gas is set to be in, for example, a range of 0 ccm to 200 ccm. A time duration of exposing the wafer100to the TiCl4, i.e., a gas supply time (irradiation time) is set to be in, for example, a range of 0.01 to 300 seconds. In this case, the temperature of the heater106is set such that the temperature of the wafer100is in, for example, a range of 100° C. to 400° C., preferably, a range of 200° C. to 400° C., and more preferably, a range of 240° C. to 350° C. When the TiCl4gas is supplied, a Ti-containing layer is formed on the TiHfN film formed in the first film-forming process to a thickness of, for example, less than one atomic layer to several atomic layers.

Next, in step S206, the TiCl4gas is purged. The process of purging the TiCl4gas (including opening/closing valves, etc.) is the same as that in step S106described above and is not redundantly described here. Similarly, the process of purging the TiCl4gas is performed by supplying N2gas, for example, in a flow rate of 20 ccm for 1 to 600 seconds.

In step S207, NH3(fourth source) is supplied into the process chamber101. In detail, the valve233bof the gas supply pipe232bis opened to supply NH3gas into the gas supply pipe232b. The flow rate of the NH3gas flowing through the gas supply pipe232bis controlled by the MFC235b. The flow rate-controlled gas is supplied into the process chamber101via the gas inlet110. In this process, the valve233amay be opened to supply N2gas via the gas supply pipe232a. Also, the valve233gmay be opened to supply N2gas via the gas supply pipe232g.

In this case, the APC valve162is appropriately controlled to set a pressure in the process chamber101to be in, for example, a range of 20 Pa to 1,330 Pa. The supply flow rate of the NH3gas controlled by the MFC235bis set to be in, for example, a range of 10 ccm to 200 ccm, and preferably, a range of 100 ccm to 200 ccm. A time duration of exposing the wafer100to the NH3, i.e., a gas supply time (irradiation time) is set to be in, for example, a range of 0.01 to 300 seconds. In this case, the temperature of the heater106is set such that the temperature of the wafer100is in, for example, a range of 100° C. to 400° C., preferably, a range of 200° C. to 400° C., and more preferably, a range of 240° C. to 350° C. The NH3gas supplied into the process chamber101reacts with at least a portion of the Ti-containing layer formed on the wafer100in step S205. Accordingly, the Ti-containing layer is nitridated to form a titanium nitride layer (TiN layer).

In step S208, the valve233bis closed to stop the supply of the NH3gas into the process chamber101. In this case, the inside of the process chamber101is vacuum-exhausted by the vacuum pump164while the APC valve162is open to remove the NH3gas (that did not react or that has contributed to the formation of a nitrogen-containing layer) remaining in the process chamber101from the process chamber101. Also, in this case, N2gas is continuously supplied into the process chamber101by opening the valve233aor233gfor while the valve233aor233gis open). The N2gas may act as a purge gas and greatly increase an effect of removing the NH3gas (that did not react or that has contributed to the formation of the nitrogen-containing layer) from the process chamber101. Purging is performed by supplying N2gas, for example, in a flow rate of 200 ccm for 1 to 60 seconds.

In this case, gases remaining in the process chamber101may not be completely removed and the inside of the process chamber101may not be completely purged, similar to the above purging processes.

One cycle including steps S205to S208described above may be performed at least once to form a metal nitride film containing titanium and nitrogen, i.e., a TiN film (step S209). This cycle is preferably repeatedly performed a plurality of times. Thus, a TiN film is formed on the TiHfN film on the wafer100to a predetermined thickness (e.g., 4 nm). Although the TiCl4gas is supplied prior to the supply of the NH3gas in the present embodiment, the NH3as may be supplied prior to the supply of the TiCl4gas.

After the TiN film is formed, N2gas is supplied into the process chamber101by opening the valve233aof the inert gas supply pipe232aor the valve233gof the inert gas supply pipe232g(or while the valve233aor233gis open). The N2gas acts as a purge gas. The inside of the process chamber101is purged with an inert gas due to the N2gas to remove a gas remaining in the process chamber101from the chamber101. Thereafter, an atmosphere in the process chamber101is replaced with the inert gas and the pressure in the process chamber101is regulated to be the same as that in the transfer chamber171.

Thereafter, the support103is moved down and the gate valve151is opened to unload the processed wafer100from the process container102by the transfer robot173.

FIG. 8is a graph showing the relationship between a process temperature and crystallinity when a TiHfN film is formed using TDEAHf.FIG. 8illustrates an analysis result of X-ray diffraction (XRD) on the MIN film when a process temperature is set to 300° C., 330° C. and 350° C. As illustrated inFIG. 8, a crystalline peak derived from HfN appears when the process temperature (film-forming temperature) is 300° C. and becomes higher when the process temperature is 330° C. or higher. As described above, a film having the crystallinity of HfN is formed when the TiHfN film is formed using TDEAHf at the process temperature ranging from 300° C. to 350° C. Here, the “film having the crystallinity of HfN” means a film including an Hf—N bond having a crystalline structure in which Hf and N are arranged regularly, i.e., a film in which a bond between Hf and N has crystallinity.

FIG. 9is a graph showing the relationship between a work function and a process temperature of a gate formed according to the flowchart ofFIG. 4. InFIG. 9, “Ethyl ligand” denotes the relationship between a work function and a process temperature when a TiHfN film is formed using TDEAHf. As illustrated inFIG. 9, if TDEAHf containing an ethyl ligand is used to form a film, a work function sharply decreased when the process temperature exceeds 300° C. at which crystallinity (a crystalline structure) derived from HfN started to appear, and is extremely low at 330° C. or higher at which a sharp crystalline peak appeared. The above result is obtained because the work function of KIN (hafnium nitride) having crystallinity is lower than that of TiN, and should be understood to mean that the work function may be modulated to various levels by controlling the crystallinity of HfN. In detail, the work functions illustrated inFIG. 9are effective work functions, and include a value of a dipole at an interface between HfO2and SiO2when HfO2is used to form a high-k film. When the work functions illustrated inFIG. 9are achieved, a time duration of supplying TiCl3and a time duration of supplying TDEAHf per cycle are 2 seconds and 10 seconds, respectively.

A work function (execution work function) of the TiN film is about 4.8 eV to 4.9 eV when HfO2is used to form a high-k film. In this regard, a work function of a TiHfN film according to the present embodiment is sufficiently lower than that of a TiN film at a range of process temperatures at which crystallinity of HfN appeared. At 300° C. to 330° C. that are in the range of process temperatures, the work function of the TiHfN film sharply changed and may be thus preferably modulated to an arbitrary level in a range of work functions that are lower than the work function of the TiN film. Also, 330° C. to 350° C. are preferable since the work function of the TiHfN film may be modulated to be far lower than that of the TiN film.

In general, a work function of an NMOS type transistor is required to be lower than 4.5 eV. As illustrated inFIG. 9, the work function of the TiHfN film according to the present embodiment sufficiently satisfies the above requirement in a range of process temperatures (particularly, at 330° C. to 350° C.) at which the crystallinity of HfN appears. Also, when a film other than an HfO2film is used as a high-k film, the TiHfN film according to the present invention has a work function that is far lower than that of the TiN film and is preferably used as a metal gate electrode of an NMOS type transistor.

Here, the crystallinity and work function of a TiHfN film formed using a source that does not contain an ethyl ligand will be described.

FIG. 10is a graph showing the relationship between a process temperature and crystallinity when a THEN film is formed using tetrakis(dimethylamino)hafnium that contains a methyl ligand (TDMAHf, Hf(N(CH3)2)4). Here, process conditions such as the flow rate of gases, pressures, etc. are the same as those when the TiHfN film ofFIG. 8is formed using TDEAHf. As illustrated inFIG. 10, a crystalline peak derived from HfN did not distinctly appear when the TiHfN film is formed using TDMAHf containing a methyl ligand.

FIG. 11is a graph showing the relationship between a process temperature and crystallinity when a TiHfN film is formed using tetrakis(ethylmethyl amino)hafnium containing an ethylmethyl ligand (TEMAHf, Hf(N(C2H5)CH3)4). Here, process conditions such as the flow rate of gases, pressures, etc. are the same as those when the TiHfN film ofFIG. 8is formed using TDEAHf. As illustrated inFIG. 11, a crystalline peak derived from HfN did not distinctly appear when the TiHfN film is formed using TEMAHf containing an ethylmethyl ligand.

The reason why the crystallinity of HfN varied according to the type of a ligand is considered as follows. The binding energy between an ethyl ligand (C2H5) and nitrogen is lower than that between either a methyl ligand (CH3) or an ethylmethyl ligand [(C2H5)CH3] and nitrogen. Thus, separation of an ethyl ligand from TDEAHf may be promoted in the temperature range of about 300° C. to 350° C. described above to cause crystallinity derived from HfN to occur. Also, when a process temperature increased, a crystalline peak became sharper, since separation of the ethyl ligand is more promoted and the intensity of energy given when a film is formed is high to promote the crystalline growth of an Hf—N bond.

The relationship between a work function and a process temperature of a TiHfN film when the TiHfN film is formed using TDMAHf or TEMAHf is as illustrated inFIG. 9. InFIG. 9, “Methyl ligand” denotes a work function and a process temperature of a TiHfN film when the TiHfN film is formed using TDMAHf, and “Ethyl Methyl ligand” denotes a work function and process temperature of a TiHfN film when the TiHfN film is formed using TEMAHf. A work function of the TiHfN film is also modulated to a relatively large degree at 300° C. to 330° C. when TDMAHf or TEMAHf is used. However, the work function of the TiHfN film is higher and a range of modulation of the work function thereof is smaller than when TDEAHf is used. Also, even if in any cases, a process temperature increased to 330° C. or higher, the work function of the TiHfN film is not decreased unlike when TDEAHf is used. As described above, TDEAHf is preferably used to largely modulate a work function so that the work function may decrease.

FIG. 12is a graph showing the composition ratios of TiHfN films formed using TDEAHf, TDMAHf and TEMAHf each containing Hf. InFIG. 12, “Ethyl” denotes the composition ratio of a TiHfN film formed using TDEAHf, “EthylMethyl” denotes the composition ratio of a TiHfN film formed using TEMAHf, and “Methyl” denotes the composition ratio of a TiHfN film formed using TDMAHf. All of the composition ratios illustrated inFIG. 12are examples when a process temperature of the wafer100is 330° C. and process conditions such as the flow rates of gases and pressures are the same as those when the TiHfN films ofFIGS. 8, 10 and 11are formed. As illustrated inFIG. 12, the content of Hf or C that works to decrease a work function is lowest when TDEAHf is used. However, as illustrated inFIG. 12, a work function is lowest when TDEAHf is used, and is greatly decreased by the crystallinity of HfN. Also, referring toFIG. 12, the reason why the content of Hf is high when TDMAHf or TEMAHf is used is considered that pyrolysis temperatures of TDMAHf and TEMAHf are low.

Next, reactions of various process gases in a process of forming the TiHfN film (the first film-forming process), will be described.FIG. 13is a graph showing the relationship between a time duration of TiCl4supply and a film-forming rate in the first film-forming process described above.FIG. 14is a graph showing the relationship between a time duration of TDEAHf supply and a film-forming rate in the first film-forming process described above.

As illustrated inFIG. 13, if TiCl4gas is supplied at a temperature that is in a range of process temperatures of the wafer100(330° C. inFIG. 13), a film-forming rate is at a critical point even when the time duration of supplying the TiCl4gas increased. That is, reaction of the TiCl4gas exhibited saturation characteristics in the range of temperatures of the wafer100described above. Thus, a film-forming rate increased in the range of process temperatures of the wafer100described above when the time duration of supplying TDEAHf gas increased as illustrated inFIG. 14. That is, reaction of the TDEAHf gas did not exhibit saturation characteristics in the range of process temperatures of the wafer100described above. Thus, in the above process of forming a TiHfN film, TiCl4showed a behavior of chemisorption but TDEAHf showed a behavior of chemical vapor growth. Accordingly, the time duration of supplying the TDEAHf gas may be controlled to adjust the content of FIN in (film thickness of) the TiHfN film, thereby effectively modulating a work function.

As described above, according to the present embodiment, a composite metal nitride film in which a bond between a second metal element and a nitrogen element has crystallinity may be formed on the wafer100by alternately supplying a first source containing a first metal element and a second source containing an ethyl ligand and the second metal element different from the first metal element to the wafer100while heating the wafer100, thereby forming a metal film, the modulation width of the work function of which is high. When noble materials are employed in the existing production lines, integration problems (processing, thermal stability, diffusion stability, etc.) may occur. However, since a film-forming process according to the present embodiment is based on the process of forming a TiN film which is a metal nitride film according to the related art, integration problems may be prevented from occurring. Also, since a TiN film is formed as a capping film on a TiHfN film in si-tu, the oxidation resistance of the TiHfN film may be improved and a work function may be prevented from increasing due to oxidation.

The present invention may be also accomplished, for example, by changing a process recipe by modifying a gas supply system of an existing substrate processing apparatus which performs a semiconductor device manufacturing process. In order to change the process recipe, a process recipe according to the present invention may be installed in the existing substrate processing apparatus via a telecommunication line or a recording medium storing the process recipe according to the present invention or the process recipe may be replaced with the process recipe according to the present invention by manipulating an I/O device of the existing substrate processing apparatus.

Also, although a case in which a work function is modulated to be lower than that of a TiN film has been described in the previous embodiment, a work function may be modulated to be higher than that of the TiN film by using a different source containing an ethyl ligand. For example, a property of an ethyl ligand that is easily separated may be used to cause a bond between other elements of a film to have crystallinity, and a work function may be increased based on characteristics of a crystalline structure of the film.

Although various exemplary embodiments of a film-forming technique according to the present invention have been described above, the present invention is not limited thereto. For example, in the present embodiment, a single-wafer apparatus has been described as an example of a substrate processing apparatus but the present invention is also applicable to a vertical processing apparatus capable of processing a plurality of wafers at a time.

According to the present invention, a work function of a metal film may be controlled.

Exemplary Embodiments of the Invention

Hereinafter, exemplary embodiments of the present invention are supplementarily noted.

Supplementary Note 1

According to an aspect of the present invention, there is provided a substrate processing apparatus including:

a process chamber configured to accommodate a substrate;

a first source supply system configured to supply a first source containing a first metal element into the process chamber;

a second source supply system configured to supply a second source into the process chamber, the second source containing an ethyl ligand and a second metal element that is different from the first metal element;

and a control unit configured to control the first source supply system and the second source supply system to form a composite metal nitride film on the substrate by alternately supplying the first source and the second source into the process chamber, wherein a bond between the second metal element and a nitrogen element in the composite metal nitride film formed on the substrate has crystallinity.

Supplementary Note 2

In the substrate processing apparatus of Supplementary note 1, the first metal element is a transition metal element.

Supplementary Note 3

In the substrate processing apparatus of Supplementary note 1, the second metal element is a transition metal element.

Supplementary Note 4

In the substrate processing apparatus of Supplementary note 1, the first metal element is titanium and the second metal element is hafnium.

Supplementary Note 5

In the substrate processing apparatus of Supplementary note 1, the first source is TiCl4containing titanium as the first metal element and the second source is TDEAHf containing hafnium as the second metal element.

Supplementary Note 6

In the substrate processing apparatus of Supplementary note 1, the control unit controls a heating unit to set a process temperature to be in a range of 330° C. to 350° C. during the forming of the composite metal nitride film.

Supplementary Note 7

In the substrate processing apparatus of Supplementary note 1, the first source exhibits a chemisorption reaction and the second source exhibits a chemical vapor growth reaction during the forming of the composite metal nitride film.

Supplementary Note 8

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, the method including a process of forming a composite metal nitride film on a substrate present in a process chamber by alternately supplying a first source and a second source to the substrate, wherein the first source contains a first metal element, the second source contains an ethyl ligand and a second metal element that is different from the first metal element, and a bond between the second metal element and a nitrogen element in the composite metal nitride film has crystallinity.

Supplementary Note 9

In the method of Supplementary note 8, the first source is TiCl4containing titanium as the first metal element and the second source is TDEAHf containing hafnium as the second metal element.

Supplementary Note 10

In the method of Supplementary note 8, a process temperature is in a range of 330° C. to 350° C. in the process of forming the composite metal nitride film.

Supplementary Note 11

In the method of Supplementary note 8, the first source exhibits a chemisorption reaction and the second source exhibits a chemical vapor growth reaction in the process of forming the composite metal nitride film.

Supplementary Note 12

According to still another aspect of the present invention, there is provided a program causing a computer to perform a sequence of forming a composite metal nitride film on a substrate present in a process chamber by alternately supplying a first source and a second source to the substrate, wherein the first source contains a first metal element, the second source contains an ethyl ligand and a second metal element that is different from the first metal element, and a bond between the second metal element and a nitrogen element in the composite metal nitride film has crystallinity.

Supplementary Note 13

According to another aspect of the present invention, there is provided a non-transitory computer-readable recording medium having recorded thereon a program causing a computer to perform a sequence of forming a composite metal nitride film on a substrate present in a process chamber by alternately supplying a first source and a second source to the substrate, wherein the first source contains a first metal element, the second source contains an ethyl ligand and a second metal element that is different from the first metal element, and a bond between the second metal element and a nitrogen element in the composite metal nitride film has crystallinity.