TWI784036B - Layer forming method - Google Patents

Abstract

There is provided a method of forming a layer, comprising depositing a seed layer on the substrate; and depositing a bulk layer on the seed layer. Depositing the seed layer comprises supplying a first precursor comprising metal and halogen atoms to the substrate; and supplying a first reactant to the substrate. Depositing the bulk layer comprises supplying a second precursor comprising metal and halogen atoms to the seed layer; and, supplying a second reactant to the seed layer.

Description

layer formation method [Cross-reference to related patent applications]

This application is a continuation-in-part of U.S. Nonprovisional Application No. 15/691,241, filed August 30, 2017, entitled "LAYER FORMING METHOD" and claims the December 18, 2017 filing US Provisional Patent Application No. 62/607,070, entitled "Layer Formation Method," both of which are incorporated herein by reference.

The present invention generally relates to a method of forming a layer on a substrate. More specifically, the present invention relates to sequentially repeating atomic layer deposition (ALD) cycles or chemical vapor deposition (CVD) procedures to form at least a portion of a layer on a substrate having gaps that occur during the fabrication of features produced in. The layers on the substrate can be used in the manufacture of semiconductor devices.

In atomic layer deposition (ALD) and chemical vapor deposition (CVD), a first precursor and a first reactant suitable for reacting to form a desired layer on the substrate are applied to the substrate. This layer can be deposited in gaps created on the substrate during the fabrication of features to fill the gaps.

In ALD, a substrate is exposed to pulses of a first precursor and a monolayer of the first precursor can be chemisorbed on the surface of the substrate. Surface sites may be occupied by all of the first precursor or by fragments of the first precursor. The reaction may be chemically self-limiting in that the first precursor does not adsorb on the substrate surface or react with the portion of the first precursor already adsorbed on the substrate surface. Next, overdose The first precursor is purged by, for example, providing an inert gas and/or removing the first precursor from the reaction chamber. The substrate is then exposed to pulses of a first reactant that chemically reacts with all or a fraction of the adsorbed first precursor until the reaction is complete and the surface is covered with a monolayer of reaction product.

It has been found that there may be a need to improve the quality of the deposited layer.

There may be a need for an improved method of forming deposited layers on a substrate. Accordingly, there may be provided a method of forming a layer comprising: providing a substrate having a gap created during feature fabrication and depositing a seed layer on the substrate; and depositing a bulk layer on the seed layer. Depositing the seed layer may include: supplying a first precursor comprising metal and halogen atoms to the substrate; and supplying a first reactant to the substrate, wherein the first precursor reacts with a portion of the first reactant to At least a portion of the seed layer is formed. Depositing the host layer may include: supplying a second precursor comprising metal and halogen atoms to the seed layer; and supplying a second reactant to the seed layer, wherein the second precursor and a portion of the second reactant reacting to form at least a portion of the bulk layer on the seed layer. The first and second precursors can be different.

By having different first and second precursors for the seed layer and the bulk layer, the properties of the seed layer and the bulk layer can be optimized, whereby the quality of the bulk layer can be improved. The first and second reactants can be the same and contain hydrogen atoms.

In some other embodiments, a method for semiconductor processing is provided. The method includes depositing a metal layer in a gap in a substrate, thereby filling the gap.

1: Pretreatment ALD cycle

2: Main body ALD cycle

3: step

5: step

7: Steps

9: Supply

11: Steps

13: Steps

15: Supply

17: Steps

19: Deposition material

21: Deposition material

23: Conformal metal layer

R1: Remove period/time

R2: time

R3: time

R4: time

These and other features, aspects and advantages of the invention disclosed herein are described below with reference to drawings of certain embodiments which are intended to illustrate and not to limit the invention.

Figures 1a and 1b show a flow diagram illustrating a method of depositing a layer according to one embodiment.

FIG. 2 shows a cross-section of a gap structure filled with a layer on a substrate according to one embodiment.

Metal layers may be required as conductive layers in semiconductor devices. Gaps created during the fabrication of features in integrated circuit devices may be filled with metal layers. The gaps can have a high aspect ratio since their depth is much greater than their width.

The gaps may extend vertically in the fabricated layer with a substantially horizontal top surface. Gaps oriented vertically and filled with metal can be used, for example, in word lines of memory volume circuits of the Dynamic Random Access Memory (DRAM) type. Gaps in the vertical direction and filled with metal can also be used, for example, in logic integrated circuits. For example, metal-filled gaps can be used as gate fills in PMOS or CMOS integrated circuits or in source/drain trench type contacts.

The gaps can also be arranged in the horizontal direction in the manufactured layer. Furthermore, the gaps may have a high aspect ratio, since their depth, now in the horizontal direction, is much greater than their width. Gaps oriented horizontally and filled with metal can be used, for example, in word lines of 3D NAND type memory volume circuits. The gaps can also be arranged in a combination of vertical and horizontal directions.

The surface of the gap may contain a type of deposition material. Alternatively, the surfaces of the gaps may contain different kinds of deposited materials. The surface of the gap may, for example, comprise aluminum oxide and/or titanium nitride. It may be difficult to deposit molybdenum on different materials in the gap when, for example, a molybdenum conductive layer may be required in the gap. It may be desired that the molybdenum layer may cover the entire surface of the gap and fill the entire gap. In addition, it may also be desirable that the molybdenum layer can cover the entire surface including gaps of different kinds of materials.

To fill the entire gap, a seed layer can be deposited in the gap and a bulk layer can be deposited on the seed layer. The seed layer can be formed by sequentially repeating the pretreatment atomic layer deposition (ALD) cycle. or, The seed layer can be formed by a chemical vapor deposition (CVD) process. The CVD process can be pulsed, wherein the first precursor is pulsed onto the substrate while the first reactant is continuously supplied onto the substrate, or vice versa. The bulk layer can be deposited on the seed layer by sequentially repeating bulk ALD cycles. Alternatively, the bulk layer can be deposited on the seed layer by a CVD process. The CVD process can be pulsed, wherein the second precursor is pulsed onto the substrate while the second reactant is continuously supplied onto the substrate, or vice versa.

Figures 1a and 1b show a flow diagram illustrating a method of depositing a layer according to one embodiment, wherein a seed layer can be deposited in the gap and a bulk layer can be deposited on the seed layer. Pretreatment ALD cycle 1 for the seed layer may be as shown in Figure 1a and bulk ALD cycle 2 for the bulk layer may be as shown in Figure 1b.

After providing the substrate with the gap in the reaction chamber in step 3, a first precursor comprising metal and halogen atoms may be supplied to the substrate in step 5 for a first supply period T1 (see FIG. 1 a ). Subsequently, further supply of the first precursor to the substrate may be stopped by eg removing, eg purging, a portion of the first precursor from the reaction chamber in step 7 for a first removal period R1. Additionally, the cycle may include supplying 9 the first reactant to the substrate for a second supply period T2. A portion of the first precursor and the first reactant can react to form at least a portion of the seed layer on the substrate. Typically, it can take several (about 50) cycles before seed layer deposition begins. The further supply of the first reactant to the substrate may eg be stopped by removing, eg purging, a portion of the first reactant from the reaction chamber in step 11 for a second removal period R1.

The first precursor and first reactant can be selected to have proper nucleation on the surface of the gap. The pretreatment ALD cycle 1 can be repeated N times to deposit the seed layer, wherein N is selected between 100 and 1000, preferably between 200 and 800, and more preferably between 300 and 600. The seed layer may have a thickness between 1 and 20 nm, preferably between 2 and 10 nm, more preferably between 3 and 7 nm.

After pretreatment, ALD cycle 1 was repeated N times. A second precursor comprising metal and halogen atoms may be supplied to the substrate in step 11 by a bulk ALD cycle 2 for a third supply time Segment T3 (see Figure 1b). This can be done in the same reaction chamber as pretreatment ALD cycle 1 of Figure 1 a or in a different reaction chamber. It may be advantageous to perform the main ALD cycle in a different reaction chamber than the pretreatment ALD cycle when the temperature requirements associated with the pretreatment cycle may be different. Therefore, substrate transfer may be necessary. Subsequently, further supply of the second precursor to the substrate may be stopped, eg by removing, eg purging, a portion of the second precursor from the reaction chamber in step 13 for a third removal period R3.

Additionally, the cycle may include supplying 15 a second reactant to the substrate for a fourth supply period T4. A portion of the second precursor and the second reactant can react to form at least a portion of the bulk layer on the substrate. The further supply of the second reactant to the substrate may eg be stopped by removing, eg purging, a portion of the second reactant from the reaction chamber in step 17 for a fourth removal period R4. The second precursor and the second reactant can be selected to have appropriate electronic properties. For example, to have low resistivity. The molybdenum film may have a resistivity of less than 3000 μΩ-cm, or less than 1000 μΩ-cm, or less than 500 μΩ-cm, or less than 200 μΩ-cm, or less than 100 μΩ-cm, or less than 50 μΩ-cm, or Below 25 μΩ-cm, or below 15 μΩ-cm or even below 10 μΩ-cm.

The bulk ALD cycle 2 on the bulk layer can be repeated M times, where M is selected between 200 and 2000, preferably between 400 and 1200, and more preferably between 600 and 1000. The host layer may have a thickness between 1 and 100 nm, preferably between 5 and 50 nm, more preferably between 10 and 30 nm.

The first and second precursors may contain the same metal atoms. The metal may be a transition metal atom. The transition metal atom may be molybdenum.

The first and second precursors may contain the same halogen atoms. The halogen atom may be chlorine. By having the same halogen, the verification of tools and procedures in the fab can be simplified because only one halogen needs to be evaluated. The first precursor may include molybdenum pentachloride (MoCl ₅ ).

During the pretreatment ALD cycle, the processing temperature in the reaction chamber can be selected between 300 and 800°C, preferably between 400 and 700°C and more preferably between 450 and 550°C. The vessel for vaporizing the first precursor may be maintained at between 40 and 100°C, preferably between 60 and 80°C and more preferably at about 70°C.

The second precursor may contain additional atoms other than metal or halogen atoms. The additional atom may be a chalcogen. The chalcogens can be oxygen, sulfur, selenium or tellurium. The second precursor may include molybdenum(VI) dioxide dichloride (MoO ₂ Cl ₂ ).

During the bulk ALD cycle, the processing temperature may be between 300 and 800°C, preferably between 400 and 700°C and more preferably between 500 and 650°C. The vessel for vaporizing the second precursor may be maintained between 20 and 150°C, preferably between 30 and 120°C and more preferably between 40 and 110°C.

Supplying the first and/or second precursor into the reaction chamber may take a duration T1 selected between 0.1 and 10 seconds, preferably between 0.5 and 5 seconds and more preferably between 0.8 and 2 seconds, T3. For example, T1 may be 1 second and T3 may be 1.3 seconds. The flow rate of the first or second precursor in the reaction chamber can be selected between 50 and 1000 sccm, preferably between 100 and 500 sccm, and more preferably between 200 and 400 sccm. The pressure in the reaction chamber can be selected between 0.1 and 100 Torr, preferably between 1 and 50 Torr, and more preferably between 4 and 20 Torr.

One or both of the first and second reactants may have hydrogen atoms. At least one of the first and second reactants may include hydrogen gas ( _H2 ). The first and second reactants can be the same. The duration T2, T4 of supplying the first and/or second reactant into the reaction chamber may take between 0.5 and 50 seconds, preferably between 1 and 10 seconds, and more preferably between 2 and 8 seconds between. The flow rate of the first or second reactant in the reaction chamber may be between 50 and 50000 sccm, preferably between 100 and 20000 sccm, and more preferably between 500 and 10000 sccm.

Silanes can be considered as the first and/or second reactant. The general formula of silane is Six H2 ( _{x +2)} , where x is an integer 1, 2, 3, 4... silane (SiH ₄ ), disilane (Si ₂ H ₆ ) or trisilane (Si ₃ H ₈ ) may be a suitable example of a first and or second reactant having a hydrogen atom.

Removing from the reaction chamber, e.g., purging away a portion of at least one of the first precursor, the first reactant, the second precursor, and the second reactant, for a duration R1, R2, R3 or R4 that may be between 0.5 and 50 seconds time, preferably between 1 and 10 seconds, and more preferably between 2 and 8 seconds. Purification can be used before placing the first After the precursor is supplied to the substrate; after the first reactant is supplied to the substrate; after the second precursor is supplied to the seed layer; and after the second reactant is supplied to the seed layer, to remove the first reactant from the reaction chamber A portion of at least one of the precursor, the first reactant, the second precursor, and the second reactant for a period of time R1, R2, R3, or R4. Removal can be accomplished by pumping and/or by providing purge gas. The purge gas may be an inert gas such as nitrogen.

The method can be used in single or batch wafer ALD tools. The method includes providing a substrate in a reaction chamber and a pretreatment ALD cycle in the reaction chamber may include: supplying a first precursor onto the substrate in the reaction chamber; purging a portion of the first precursor from the reaction chamber; The first reactant is supplied on the substrate in the reaction chamber; and a part of the first reactant is purged from the reaction chamber. Additionally, the method includes providing a substrate in a reaction chamber and the bulk ALD cycle in the reaction chamber includes: supplying a second precursor onto the substrate in the reaction chamber; purging a portion of the second precursor from the reaction chamber; A second reactant is supplied onto the substrate in the reaction chamber; and a portion of the second reactant is purged from the reaction chamber.

Exemplary single wafer reactors specifically designed to perform ALD procedures are commercially available from ASM International NV (Almere, The Netherlands) under the trade names Pulsar®, Emerald®, Dragon®, and Eagle®. The method can also be performed in a batch wafer reactor, such as a vertical furnace. For example, the deposition procedure can be performed in an A412 ^™ vertical furnace also available from ASM International NV. The furnace may have a processing chamber capable of holding a load of 150 semiconductor substrates or wafers with a diameter of 300mm.

The wafer reactor may be provided with a controller and memory capable of controlling the reactor. The memory can be programmed to, when executed on the controller, supply precursors and reactants to the reaction chamber in accordance with embodiments of the present invention.

FIG. 2 shows a cross-section of a gap structure filled with a layer on a substrate according to an embodiment of the present invention. As shown, the gap can extend both vertically and horizontally in the fabricated layer with a substantially horizontal top surface.

The gaps can have a high aspect ratio, since the depth in the vertical and/or horizontal direction is much greater than the width. For example, in the vertical direction, the gap has a width of 207nm at the top, 169nm in the middle and 149nm at the bottom, while the depth of the gap is much greater at 432nm. For example, in the horizontal direction, the first gap has a width from the top of 34nm, while the depth of the gap is much larger, 163nm (rounded). The aspect ratio of the gap (gap depth/gap width) can be greater than about 2, greater than about 5, greater than about 10, greater than about 20, greater than about 50, greater than about 75, or in some cases even greater than about 100 or greater than about 150 or greater than about 200.

It can be noted that the aspect ratio of the gap can be difficult to measure, but in this paper, the aspect ratio can be replaced by the surface enhancement ratio (surface enhancement ratio), which can be compared to the total surface area of the gap in the wafer or part of the wafer. The ratio of the planar surface area of a wafer or portion of a wafer. The surface enhancement ratio of the gap (surface gap/surface wafer) can be greater than about 2, greater than about 5, greater than about 10, greater than about 20, greater than about 50, greater than about 75, or in some cases even greater than about 100 or greater than About 150 or greater than about 200.

The surface of the gap may contain different kinds of deposited materials 19,21. The surface may for example comprise Al ₂ O ₃ or TiN.

A conformal metal layer 23 is deposited on the surface of the gap by sequentially repeating pretreatment ALD cycles with a first precursor to deposit a seed layer and by sequentially repeating bulk ALD cycles with a second precursor to deposit a bulk layer. Details of the method used are shown in Figures 1a and 1b and the associated description. In some embodiments, the deposited Mo-containing film can have a step coverage of greater than about 50%, greater than about 80%, greater than about 90%, greater than about 95%, greater than about 98%, greater than about 99%.

The first and second precursors may contain the same metal atoms, for example transition metal atoms such as molybdenum. The first and second precursors may contain the same halogen atoms, such as chlorine. The first precursor may include MoCl5. The second precursor may contain additional atoms other than metal or halogen atoms, for example chalcogen atoms, such as oxygen. The second precursor may include molybdenum(VI) dioxide dichloride (MoO ₂ Cl ₂ ). The method can be performed in atomic layer deposition equipment. Such deposition procedures can be performed, for example, in EMERALD® XPALD equipment.

The first and second reactants are hydrogen gas (H ₂ ), which is supplied in the reaction chamber at a flow rate of 495 sccm for a time T2, T4 of 5 seconds. The purge gas nitrogen was used after supplying the first precursor; after supplying the first reactant; after supplying the second precursor; and after supplying the second reactant, for a period of 5 seconds R1, R2, R3 or R4.

During the pretreatment and bulk ALD cycles, the processing temperature was about 550°C and the pressure was about 10 Torr. The vessel in which the first precursor is vaporized is about 70°C. The vessel in which the second precursor is vaporized is about 35°C.

A seed layer of about 4.6 nm was deposited using a pretreatment ALD cycle for 500 cycles, and a bulk layer of about 21.4 nm was deposited using a bulk ALD cycle for 800 cycles. As shown, the molybdenum layer 23 was deposited very uniformly on the surface of the gap and had a total thickness of about 26 nm.

The orientation of the gap, whether horizontal or vertical, and the width of the gap do not appear to materially affect the thickness of layer 23 . Furthermore, the material of the surface, whether it be Al ₂ O ₃ 19 or TiN 21 does not appear to affect the thickness of layer 23 . In this way, it is possible to produce metal-filled gaps with good uniformity.

The method can also be used in space atomic layer deposition equipment. In spatial ALD, precursors and reactants are continuously supplied in different physical zones and the substrate is moved between the zones. At least two sections may be provided, in which case half-reactions may be performed in the presence of the substrate. If a substrate is present in such a half-reaction zone, a monolayer can be formed from either the first or the second precursor. Next, the substrate moves to another half-reaction zone where ALD cycling is completed using either the first or second reactant to form an ALD monolayer. Alternatively, the substrate position can be fixed and the gas supply can be moved, or some combination of the two. This procedure can be repeated for thicker films.

According to one embodiment of the spatial ALD apparatus, the method comprises: placing the substrate into a reaction chamber comprising a plurality of sections, each section being separated from an adjacent section by an air curtain; supplying a first precursor onto the substrate in a first section of the reaction chamber; moving the substrate surface laterally to the reaction chamber through the gas curtain into a second section of the reaction chamber; supplying the first reactant to the reaction chamber forming a seed layer on a substrate in a second section of the chamber; moving the substrate surface laterally to the reaction chamber through the air curtain; and repeatedly supplying the first precursor and reactant, including moving the substrate surface lateral to the reaction chamber ground to form a seed layer.

To form the bulk layer, the method further includes: placing the substrate into a reaction chamber comprising a plurality of sections, each section being separated from an adjacent section by a gas curtain; supplying a second precursor to a second precursor of the reaction chamber. on the substrate in one section; moving the substrate surface laterally with respect to the reaction chamber through the air curtain into a second section of the reaction chamber; supplying a second reactant onto the substrate in the second section of the reaction chamber to forming the bulk layer; moving the substrate surface laterally with respect to the reaction chamber through the air curtain; and repeatedly supplying the second precursor and reactant, including moving the substrate surface laterally with respect to the reaction chamber to form the bulk layer.

The first and second precursors can be different. The first and second reactants can be the same and contain hydrogen atoms.

According to one embodiment, the seed layer can be deposited by a chemical vapor deposition (CVD) process, wherein the first precursor and the first reactant are simultaneously supplied to the substrate. The host layer can be deposited by CVD process, wherein the second precursor and the second reactant can also be supplied to the substrate at the same time.

The CVD process may be a pulsed CVD process in which the precursor system is pulsed to the substrate while the reactants are continuously supplied to the substrate. An advantage of this may be that a higher concentration of reactants reduces the concentration of the halogen. High concentrations of halogens can damage semiconductor devices on substrates.

For example, in a pulsed CVD procedure for the seed layer, the first precursor five Molybdenum chloride (MoCl5) can be provided alternately with 1 second pulses and 5 second purge gas flows. The first reactant hydrogen can be continuously supplied at a flow rate of 500 seem and the substrate can be maintained at 550°C.

An exemplary single wafer reactor designed specifically to perform CVD procedures is commercially available from ASM International NV (Almere, The Netherlands) under the trade name Dragon®. The method can also be performed in a batch wafer reactor, such as a vertical furnace. For example, the deposition procedure can be performed in an A400 ^™ or A412 ^™ vertical furnace, also available from ASM International NV. The furnace may have a processing chamber capable of holding a load of 150 semiconductor substrates or wafers.

For manufacturing 3D NAND memory, word lines may have gaps that require low-resistivity metal fill. Existing solutions utilize TiN as a seed layer for CVD tungsten gapfill. For current fluorine-based tungsten deposition procedures, fluorine from the WF6 precursor can diffuse. A thicker (=3nm) TiN barrier layer may be necessary to prevent fluorine diffusion and the attack of the diffused fluorine on the high-k Al2O3 film. However, the high resistivity of the tin film (800 [mu][Omega]-cm at 3 nm) leads to an increase in resistivity of the TiN/W stack, which may be undesirable.

There may be a need for an improved method of forming deposited layers on substrates having low resistivity while being free of fluorine. Accordingly, there may be provided a method of forming a layer comprising: providing a substrate having gaps created during feature fabrication; depositing a seed layer on the substrate; and depositing a bulk layer on the seed layer . Depositing the bulk layer may include supplying a second precursor comprising a transition metal such as tungsten to deposit the bulk layer on top of the seed layer.

The second precursor may contain a halogen, such as chlorine, to deposit the bulk layer. The second precursor may be tungsten (V) chloride (WCl ₅ ) or tungsten (VI) chloride (WCl ₆ ). The bulk layer can be deposited by reacting tungsten(V) chloride (WCl ₅ ) or tungsten(VI) chloride (WCl ₆ ) with hydrogen H ₂ in ALD or CVD mode of operation. For example, the reaction of WCl ₅ can be achieved at a temperature of 450°C and a pressure of 40 Torr. The precursors can be provided in ALD or CVD modes of operation.

The seed layer can be deposited by reacting a first precursor comprising molybdenum with hydrogen gas. The resistivity of the seed layer using molybdenum can be 107 μΩ-cm (3nm), which is smaller than that of the TiN layer. Especially for a stack thickness of 15nm (equivalent to a gapfill in a 30nm CD structure), good gapfill is achieved using this method. By depositing a bulk layer on top of the seed layer using tungsten(V)chloride ( _WCl5 ) or tungsten( _VI )chloride (WCl6), it is possible to deposit a tungsten layer without using fluorine and still have low resistivity. The precursor for the seed layer may include a transition metal such as molybdenum (Mo), a halogen such as chlorine (Cl), and optionally a chalcogen atom such as oxygen (O). The precursor of the seed layer can be, for example, pentachloride (MoCl ₅ ) or molybdenum(VI) dichloride (MoO ₂ Cl ₂ ), both of which react with hydrogen. If molybdenum pentachloride (MoCl ₅ ) is used together with molybdenum dioxide dichloride (MoO ₂ Cl ₂ ), the partial pressure of hydrogen can be reduced by 100 times.

The deposition rate of the molybdenum seed layer may be 1.2 Angstroms per cycle. For comparison, the deposition rate of the TiN seed layer may be 0.6 Angstroms per cycle under the same conditions. The deposition rate of the molybdenum seed layer may thus be sufficient.

The metal deposited on the seed layer can be copper. The second precursor may include copper. The second precursor may contain a halogen, such as chlorine, to deposit the bulk layer. The second precursor may include copper(II) chloride (CuCl ₂ ) or cuprous chloride (CuCl). These precursors can be provided in ALD or CVD modes of operation that react with hydrogen.

The metal deposited on the seed layer may be a transition or noble metal from the following group: Ti, V, Cr, Mn, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir and Pt. In some embodiments, this layer may comprise Co or Ni.

In other embodiments, the seed or bulk layer can comprise less than about 40 at%, less than about 30 at%, less than about 20 at%, less than about 10 at%, less than about 5 at%, or even less than about 2 at% oxygen. In other embodiments, the seed or bulk layer can comprise less than about 30 atomic %, less than about 20 atomic %, less than about 10 atomic %, or less than about 5 atomic %, or less than about 2 atomic %, or even less than about 1 atomic % hydrogen. In some embodiments, the seed or bulk layer can comprise less than about 10 at%, or less than about 5 at%, less than about 1 at%, or even less than about 0.5 at% halogen atoms or chlorine. In still other embodiments, the seed or host layer can comprise less than about 10 atomic %, or less than about 5 atomic %, or less than about 2 atomic %, or less than to about 1 atomic percent, or even less than about 0.5 atomic percent carbon. In the embodiments outlined herein, the atomic percent (atomic %) concentrations of elements can be determined using Rutherford backscattering (RBS).

In some embodiments of the present invention, forming a semiconductor device structure, such as a semiconductor device structure may include forming a gate electrode structure comprising a molybdenum film, the gate electrode structure having an effective work function greater than about 4.9 eV, or greater than about 5.0 eV , or greater than about 5.1 eV, or greater than about 5.2 eV, or greater than about 5.3 eV, or even greater than about 5.4 eV. In some embodiments, the effective work function values provided above can be exhibited by electrode structures comprising molybdenum films having a thickness of less than about 100 angstroms, or less than about 50 angstroms, or less than about 40 angstroms, or even less than about 30 angstroms.

Those skilled in the art will understand that various omissions, additions and modifications can be made to the above-mentioned programs and structures without departing from the scope of the present invention. It is contemplated that various combinations or subcombinations of particular features and aspects of the embodiments can be made and still be within the scope of the description. Various features and aspects of the disclosed embodiments may be combined or substituted in sequence. All such modifications and variations are intended to come within the scope of the invention as defined by the appended claims.

Claims (28)

A method of forming a layer comprising: providing a substrate into a reaction chamber, the substrate having a plurality of gaps created during fabrication of a feature; depositing a seed layer on the substrate; and depositing a bulk layer On the seed layer, wherein depositing the seed layer includes: supplying a first precursor comprising metal and halogen atoms to the substrate; and supplying a first reactant to the substrate, wherein the first precursor and the A portion of the first reactant reacts to form at least a portion of the seed layer; wherein, depositing the host layer includes: supplying a second precursor comprising metal and halogen atoms to the seed layer; and supplying a second reactant to the seed layer, wherein the second precursor and a portion of the second reactant react to form at least a portion of the bulk layer on the seed layer, and wherein the first and second precursor systems are different. The method of claim 1, wherein at least one of the first and second reactants comprises a hydrogen atom. The method of claim 2, wherein at least one of the first and second reactants comprises hydrogen (H ₂ ). The method of claim 1, wherein the first and second precursors contain the same metal atoms. The method according to claim 1, wherein at least one of the first and second precursors comprises transition metal atoms. The method according to claim 5, wherein the transition metal atom is molybdenum. The method according to claim 1, wherein the first and second precursors contain the same halogen atoms. The method according to claim 1, wherein the halogen atom is chlorine. The method according to claim 1, wherein the first precursor comprises molybdenum pentachloride (MoCl ₅ ). The method of claim 1, wherein the second precursor comprises other atoms other than metal or halogen atoms. The method according to claim 10, wherein the additional atom is a chalcogen atom. The method according to claim 11, wherein the chalcogen atom is oxygen. The method according to claim 12, wherein the second precursor comprises molybdenum(VI) dichloride (MoO ₂ Cl ₂ ). The method of claim 1, wherein at least one of the first and second precursors is supplied into the reaction chamber in pulses and the pulses are between 0.1 and 10 seconds. The method of claim 1, wherein the flow rate of the first or second precursor into the reaction chamber is between 50 and 1000 sccm. The method of claim 1, wherein the flow rate of the first or second reactant to the reaction chamber is between 50 and 50000 sccm. The method of claim 1, wherein the pressure in the reaction chamber is between 0.1 and 100 Torr. The method according to claim 1, wherein the processing temperature in the reaction chamber is between 300 and 800°C. The method of claim 1, wherein depositing the seed layer comprises repeating an atomic layer deposition (ALD) cycle comprising sequentially supplying the first precursor to the substrate and supplying the first reactant to the substrate; and/or Depositing the bulk layer includes repeating an atomic layer deposition (ALD) cycle comprising sequentially supplying the second precursor to the substrate and supplying the second reactant to the substrate. The method as claimed in item 19, wherein, after the first precursor, the first reactant, The second precursor or the second reactant is supplied between the substrates to purge the substrates for a time between 0.5 and 50 seconds. The method of claim 19, wherein it takes between 0.5 and 50 seconds to supply the first and/or second reactants into the reaction chamber. The method of claim 19, wherein the pretreatment ALD cycle is repeated between 100 and 1000 times for depositing the seed layer and the bulk ALD cycle is repeated between 200 and 2000 times for depositing the bulk layer times. The method of claim 1, wherein depositing at least one of the seed and bulk layers comprises a chemical vapor deposition (CVD) process, wherein the precursor system and the reactants are simultaneously supplied to the substrate. The method according to claim 5, wherein the transition metal atom is tungsten (W). The method according to claim 1, wherein the second precursor comprises tungsten (W). The method according to claim 25, wherein the second precursor comprises tungsten (V) chloride (WCl ₅ ) or tungsten (VI) chloride (WCl ₆ ). The method according to claim 1, wherein the second precursor comprises copper. The method according to claim 24, wherein the second precursor comprises copper(II) chloride (CuCl ₂ ) or cuprous chloride (CuCl).

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