JP4190175B2 - Method for manufacturing semiconductor device having high dielectric constant metal oxide film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a semiconductor device.SetHigh dielectric constant metal oxide that is related to a manufacturing method, and particularly suitable for use as a gate insulating film of a semiconductor device having a MIS (Metal Insulator Semiconductor) structurefilmFor manufacturing a semiconductor device havingTo the lawIt is related.
[0002]
[Prior art]
With the miniaturization of silicon semiconductor integrated circuits, the dimensions of MIS (Metal-Insulator-semiconductor) semiconductor elements are miniaturized. According to the 2000 update version of ITRS (International Technology Roadmap for Semiconductors), a 60 nm technology node is equivalent to a silicon oxide equivalent film thickness (Equivalent Physical Oxide Thickness; hereinafter referred to as EOT-1.2). A gate insulating film is needed. A silicon oxide film or silicon oxynitride film is insufficient to realize a gate insulating film in which leakage current is suppressed with this film thickness, and an insulating film having a high dielectric constant, that is, a high dielectric constant metal oxide insulating film Is needed.
[0003]
As a next generation high dielectric constant metal oxide insulating film which has been actively researched in recent years, Ta₂O_FiveTiO₂, Al₂O_Three, ZrO₂, HfO₂Zr silicate (ZrSiOx) and Hf silicate (HfSiOx). In particular, ZrO has good thermodynamic stability on a Si substrate, and has a large dielectric constant and band gap.₂, HfO₂These silicates are considered promising as gate insulating films of the sub-1 nm generation.
[0004]
However, the following problems have been pointed out in the thermal stability of the interface between these high dielectric constant metal oxide insulating films and the Si substrate. One is that the heat treatment after the formation of the insulating film is usually performed in a temperature range of 950 ° C. to 1000 ° C. at a pressure of 532 Pa in nitrogen, for example. However, under these conditions, the oxidized species (O₂, H₂O) and the metal oxide insulating film contains oxidizing species (O₂, H₂O) diffusion is relatively fast, and in various heat treatment steps during the manufacturing process of the semiconductor device, a small amount of oxidized species in the atmosphere easily passes through the insulating film, and thick SiO is present at the insulating film / Si substrate interface.₂The point is that a film is formed. As a result, the dielectric constant of the entire film is lowered, leading to an increase in EOT.
[0005]
Conversely, in the case of heat treatment in an ultra-high vacuum (ultra high vacuum; hereinafter referred to as UHV) in which the partial pressure of oxidizing species in the heat treatment atmosphere is reduced, the interface between the high dielectric insulating film and the Si substrate is performed by heat treatment at 900 ° C. or higher. It has been confirmed that a silicidation (MSix) reaction occurs and deterioration of insulating properties and interface flatness occurs (2001 MRS Spring Meeting, Symposium K, Gate Stack and Silicide Issues in Si Processing II, etc.). This phenomenon occurs not only at the metal oxide insulating film / Si substrate interface but also at the interface with the poly-Si or poly-SiGe gate electrode. Regarding these phenomena, for example, ZrO₂The following reactions are considered.
ZrO_x+ (X + 2) Si → ZrSi₂+ XSiO ↑
(D. Wicksana et al., MRS K1.7) (1)
Si + SiO₂+ ZrO₂→ ZrSi₂+ ZrSi + SiO ↑
(M. A. Griberyuk et al., MRS K2.8) (2)
ZrO₂+ 6SiO ↑ → ZrSi₂+ 4SiO₂
(T. S. Jeon et al., Appl. Phys. Lett. 78, 368 (2001).) (3)
These reactions are ZrO₂Not limited to HfO₂And also in silicates containing them. From these reaction equations, it can be seen that generation of SiO gas at the gate electrode / metal oxide insulating film interface or the metal oxide insulating film / Si substrate interface triggers the formation of silicide.
[0006]
From the above, SiO at the metal oxide insulating film / Si substrate interface₂In order not to increase the film, the partial pressure of the oxidizing species in the atmosphere must be lowered, but there is a reciprocal relationship that if it is lowered too much, formation of silicide occurs. The range of the optimum partial pressure of oxidizing species that suppresses oxidation and silicidation is very narrow, and in applying these high dielectric metal oxide insulating films to the current semiconductor processes that have many high-temperature thermal processes such as activation heat treatment, etc. SiO at the gate electrode / metal oxide insulating film interface or metal oxide insulating film / Si substrate interface metal oxide insulating film / Si substrate interface₂It has been difficult to suppress the formation of a film or a silicide film.
[0007]
[Problems to be solved by the invention]
As described above, in the heat treatment step after the formation of the high dielectric constant metal oxide insulating film, a thick SiO is easily formed on the metal oxide insulating film / Si substrate interface by a slight amount of oxygen and water in the atmosphere.₂A film is formed, resulting in a decrease in dielectric constant. On the other hand, when heating is performed in a low oxygen / moisture pressure atmosphere such as UHV, silicide is formed at the interface between the metal oxide insulating film and the Si substrate, which causes deterioration of insulation and flatness of the interface.
[0008]
The present invention has been made to solve these problems, and SiO at the metal oxide insulating film / Si substrate interface.₂The increase in the film and the formation of silicide at the gate electrode / metal oxide insulating film interface and the metal oxide insulating film / Si substrate interface are suppressed, and the gate electrode / metal oxide insulating film and metal oxide insulating film / Si substrate interface are suppressed. It is an object of the present invention to provide a semiconductor device having a highly reliable insulating film with low leakage current, and capable of both reducing the roughness and suppressing the decrease in the dielectric constant of the high dielectric constant metal oxide insulating film.
[0009]
[Means for Solving the Problems]
  In order to achieve the above object, a first semiconductor device manufacturing method according to the present invention includes:
  Forming a high dielectric constant metal oxide film on a silicon substrate;
  After the high dielectric constant metal oxide film forming step,With the high dielectric constant metal oxide film exposed,The sum of the partial pressures of oxygen and water is 133 * 1011.703-18114 / TPa (T is the heat treatment temperature (K)) or less, andAt least one of He or NePerforming a heat treatment at 650 ° C. or higher in an atmosphere in which a gas exists;
  Using the high dielectric constant metal oxide filmMIS type transistorComprising the step of forming
A method for manufacturing a semiconductor device having a high dielectric constant metal oxide film.
[0010]
In the first manufacturing method, the sum of partial pressures of oxygen and water contained in the atmosphere of the heat treatment step is 133 * 10.^{8.903-18114 / T}It is desirable that the temperature be lower than Pa (T is the heat treatment temperature (K)).
[0011]
  In addition, a second method for manufacturing a semiconductor device according to the present invention includes:
  Forming a high dielectric constant metal oxide film on a silicon substrate;
  Forming a thin film on the high dielectric constant metal oxide film;
  Patterning the thin film;
After the step of patterning the thin film, the partial pressure of oxygen and water is 133 * 10 with the high dielectric constant metal oxide film exposed. ^{11.703-18114 / T} Under an atmosphere where Pa (T is the heat treatment temperature (K)) or less and a gas that is at least one of He or Ne is presentAnd a step of performing a heat treatment at 650 ° C. or higher,
  Using the high dielectric constant metal oxide filmMIS type transistorA method of manufacturing a semiconductor device having a high dielectric constant metal oxide film.
[0012]
  In the second production method, the sum of partial pressures of oxygen and water contained in the atmosphere of the heat treatment step is 133 * 10.^{8.903-18114 / T}It is desirable that the temperature be lower than Pa (T is the heat treatment temperature (K)).
[0016]
According to the first and second semiconductor device manufacturing methods of the present invention, SiO inevitably formed at the metal oxide insulating film / Si substrate interface.₂The increase in the film and the formation of silicide at the gate electrode / metal oxide insulating film interface and the metal oxide insulating film / Si substrate interface are suppressed, and the gate electrode / metal oxide insulating film and metal oxide insulating film / Si substrate interface are suppressed. It is possible to achieve both a reduction in roughness and a suppression of a decrease in dielectric constant of a high dielectric constant metal oxide insulating film, and a semiconductor device having a highly reliable insulating film with little leakage current is provided.
[0018]
In this specification, the high dielectric constant metal oxide means a metal oxide having a relative dielectric constant higher than that of silicon oxide, and also includes a metal oxynitride, a silicate containing metal, silicon, and oxygen as constituent elements. It shall be in that category. For example, ZrO₂, HfO₂, BeO, MgO, CaO, SrO, BaO, Y₂O_Three, CeO₂, PrxOy, Nd₂O_Three, ThO₂, RuO₂, IrO₂, Al₂O_Three, In₂O_Three, ZrON, HfON, ZrSiO_Four, HfSiO_FourThe present invention can also be applied to the formation of a film or the like. Particularly desirable are zirconium, hafnium oxides, oxynitrides or silicates from the viewpoint of thermodynamic stability with Si, low defects and low deliquescence. The high dielectric constant metal oxide film includes a mixed film containing a high dielectric constant metal oxide and a high dielectric constant metal oxide film in addition to a film made of a high dielectric constant metal oxide, oxynitride or silicate alone. It may be a laminated film.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention (hereinafter referred to as an example) will be described with reference to the drawings.
(First embodiment)
The first manufacturing method of the present invention will be described by taking MIS transistor formation as an example.
First, as shown in FIG. 1, a deep trench that plays a role of element isolation is formed on the surface of a single crystal p-type silicon substrate 11, and is filled with a silicon oxide film 13 by a CVD method to form an element isolation region 12. . (First step)
Next, as shown in FIG. 2, ZrO, which is a high dielectric constant metal oxide film.₂A film 14 is formed (ZrO₂The method for forming the film will be described later in detail). (Second step)
Next, as shown in FIG.₂A polysilicon film 15 is formed as a gate electrode on the film 14 by a CVD method. (Third step)
Next, as shown in FIG. 4, a photoresist pattern 16 is formed on the polysilicon 15. (4th process)
Next, as shown in FIG. 5, the polysilicon film 15 is subjected to reactive ion etching using the photoresist pattern 16 as a mask to form a first gate electrode 15.
(5th process)
Next, arsenic ion implantation is performed, for example, with an acceleration voltage of 40 keV and a dose amount of 2 × 10.¹⁵cm^-2By performing the activation heat treatment under the conditions of n, high impurity concentration n⁺Type gate electrode 15, n⁺Type source region 17, n⁺A type drain region 18 is formed simultaneously. (6th process)
Next, as shown in FIG. 6, a 300 nm silicon oxide film is deposited on the entire surface by the CVD method to form an interlayer insulating film 19. Thereafter, a photoresist pattern (not shown) for forming a contact hole is formed on the interlayer insulating film 19, and the interlayer insulating film 19 is etched by reactive ion etching using this as a mask to open a contact hole. Finally, after an Al film is formed on the entire surface by sputtering, this is patterned to form the source electrode 110, the drain electrode 111, and the second gate electrode 112, thereby completing the n-type MIS transistor. (Seventh step) In this embodiment, the manufacturing process of the n-type MIS transistor is shown. However, the p-type MIS transistor is different in that the conductivity type is switched between the n-type and the p-type, and the basic manufacturing process is different. The process is exactly the same.
[0020]
Here, ZrO which is a high dielectric constant metal oxide insulating film₂Details of the formation process of the film 14 will be described.
[0021]
First, a hydrochloric acid / ozone water treatment was used as a pretreatment to effectively remove surface contamination on the silicon wafer. Thereby, about 1 nm of Chemical Oxide is formed on the Si surface (to reduce EOT, dilute hydrofluoric acid treatment may be added after this).
[0022]
Next, the pre-processed wafer is transferred into the sputtering apparatus. Keep the wafer temperature at room temperature, ZrO₂Ar / O using the target₂Sputtering with gas RF plasma (400 W) is performed, and about 2 nm of ZrO on Chemical Oxide.₂A film was formed.
[0023]
Next, ZrO₂Heat treatment for densification of the film and reduction of defects was performed. The heat treatment conditions at this time are as follows.
<In He atmosphere>
Background vacuum: 133 * 5.4E^-TenPa
He pressure: 133 Pa
Sum of oxygen and moisture pressure in the atmosphere: 133 * 1E^-9Pa
Substrate temperature: 920 ° C
Heating time: 10 minutes
For comparison, only a heat treatment condition was changed, and a sample was prepared in the same manner as in the above example.
[0024]
The heat treatment conditions are as follows.
<During UHV>
Degree of vacuum: 133 * 1E^-9Pa
Substrate temperature: 920 ° C
Heating time: 10 minutes
<N₂Atmosphere>
Background vacuum: 133 * 5.4E^-TenPa,
N₂Pressure: 133 Pa,
Oxygen and moisture pressure are the same as in He,
Substrate temperature: 920 ° C
ZrO before and after heat treatment for the above three types of samples₂/ SiO₂In-situ X-ray Photoelectron Spectroscopy (hereinafter referred to as In-situ X-ray Photoelectron Spectroscopy)
(Referred to as XPS).
[0025]
FIG. 7 shows changes in Zr3d and Si2p spectra under various heat treatment conditions. The X-ray source was measured at a MgKα photoelectron escape angle of 45 degrees. For comparison, the results in UHV and N2 atmosphere are also shown.
[0026]
According to the Zr3d spectrum, no ZrSix is formed in the He heat treatment despite the high temperature heat treatment exceeding 900 ° C. Where ZrO₂It is ZrO that the peak shape becomes sharp and slightly shifts to the higher energy side.₂This is because as the crystallization of the layer progresses, the insulating property is improved, and charge-up due to X-ray irradiation occurs. On the other hand, in UHV and N₂Inside is ZrO₂It can be confirmed that the layer disappeared completely and ZrSix was formed. This is the same as the conventional report example, because the reactions of the formulas (1) to (3) occurred. Also in the Si2p spectrum, it can be confirmed that the reduction of the interface SiOx film does not occur by the heat treatment in the He atmosphere. Again, the broad SiOx peak is sharpened by heat treatment and shifted to the higher energy side, making it more thermally stable.₂It turns out that it changed into the film. However, SiO₂The amount of membrane has not increased. In other atmospheres, the SiOx film is reduced and ZrSix is formed.₂It can be seen that nitriding further progresses and a SiNx film is formed on the ZrSix surface. In addition, the ZrSix intensity of Si2p increases and the ZrSix intensity of Zr3d increases to ZrO.₂Since it is reduced compared to the strength, ZrO₂It can be seen that most of the film evaporates as the SiO gas is desorbed from the lower layer, and a small amount of Zr atoms remaining react with the surface of the clean Si substrate to form a ZrSix layer.
[0027]
Next, it was confirmed to what extent the heat treatment effect in this He atmosphere was effective with respect to the residual oxidizing species partial pressure and heating temperature.
[0028]
FIG. 8 shows the oxidation-reduction boundary of the oxidizing species partial pressure (sum of oxygen and moisture pressure) with respect to various heat treatment temperatures. Black circle is SiO₂/ Reduction boundary (Si + SiO when examining the Si / Si interface)₂← → 2SiO ↑), the upper side of the solid line connecting the black circles is the oxidation region (SiO 2 formation region) and the lower side is the reduction region (SiO gas formation region). The lower region has an oxidizing species partial pressure of 133 * 10^{11.703-18114 / T}It can be described as a range below Pa (T is the heat treatment temperature (K)). In addition, this reduction region is SiO₂It varies slightly depending on the metal oxide insulating film formed on the surface. As an example, ZrO₂/ SiO₂The experimental value of the reduction boundary in the / Si structure is indicated by a black square. The region below the dotted line connecting the black squares is a reduction region (silicided region). This is because the partial pressure of oxidizing species is 133 * 10^{8.903-18114 / T}It can be described as Pa or less (T is the heat treatment temperature (K)). SiO₂It can be seen that the boundary line is lowered by about 3 digits compared to / Si. The reason why the boundary line goes down is that ZrO₂This is because the catalytic action acts when the oxidized species diffuse in the film and the oxidized species are activated, so that the reduction reaction is less likely to occur even at a lower partial pressure of the oxidized species.
[0029]
In the region between the solid line and the dotted line, ZrO₂/ SiO₂In the case of / Si, it is a transition region, no reduction reaction occurs, and SiO₂The amount is an area that does not change. However, this range is extremely narrow, and it is difficult to control the atmosphere in this region.
[0030]
In the case of a high dielectric constant metal oxide insulating film, by adding a rare gas to the atmosphere of the present invention, not only the region below the solid line region but also the region below the dotted line region can suppress the oxidation reaction. Demonstrates reduction reaction (silicidation) suppression effect. The range in which the partial pressure of oxidizing species during He 1133Pa heat treatment is varied is indicated by a black triangle. This range is indicated by ZrO.₂/ SiO₂In spite of the / Si reduction reaction region, there was no silicidation as shown in FIG. 7, and no increase in interfacial oxide film thickness was confirmed. Other atmosphere (UHV, N₂) Showed that ZrSix was formed, so that the addition of He was effective within the oxidizing species partial pressure range.
[0031]
However, in the first manufacturing method of the present invention, unless a thin film serving as a cap layer is formed on the high dielectric metal oxide insulating film, the oxidizing species ( Oxygen and H₂It is necessary to control the partial pressure of O) to a region below the solid line.
[0032]
Next, the temperature range where He addition can be applied was also confirmed. SiO by Electron Spin Resonance (hereinafter referred to as ESR)₂According to / Si interface evaluation, SiO₂Since the temperature at which the dangling bond is formed at the / Si interface is 650 ° C. or higher, the maximum effect is exhibited by adding a rare gas in the range of 650 ° C. or higher in terms of suppressing SiO desorption due to bond breaking. It became clear to do. On the other hand, the upper limit of the heat treatment temperature is not particularly limited, but ZrO₂It is desirable that the temperature is 1200 ° C. or lower at which the film does not deteriorate. More preferably, it is 1050 degrees C or less.
[0033]
From the above, in the first production method of the present invention, the conditions under which He is most effective are that the substrate temperature is 650 ° C. or higher (the region on the left side from the vertical broken line in FIG. 8) and the oxidizing species partial pressure is 133 * 10^{11.703-18114 / T}A range below Pa (T is the heat treatment temperature (K)) (region below the solid line connecting the black circles in FIG. 8), more preferably 133 * 10.^{8.903-18114 / T}The range is less than Pa (region below the dotted line connecting the black squares in FIG. 8).
[0034]
The above results are mainly from ZrO₂Although described with respect to the membrane, HfO₂The same improvement effect has been confirmed for the film.
[0035]
The mechanism of silicidation suppression by adding a rare gas (for example, He) will be described with reference to FIG. In the conventional method, silicide and SiO gas are formed at the interface by the reaction of the formula (2), and ZrO₂The silicidation further proceeds because the SiO gas diffusing in the film causes the reaction of the formula (3). On the other hand, in the present invention in which He is added to the heat treatment atmosphere, since He has a smaller atomic radius and mass than nitrogen atoms, the diffusion rate in the insulating film is high, and He collides with SiO which is going to diffuse outward from the interface. In addition, there is an effect of physically suppressing detachment. At the same time, the generation of SiO itself is suppressed in order to cool the Si—O bond at the interface where He thermally vibrates (quenching effect). Also, the small atomic radius means that SiO₂Increase the solid solubility limit of He in the SiO₂Medium diffusion can be further suppressed. In addition, since He is an inert gas, an oxidation / reduction reaction by the additive gas itself does not occur, so that the quality of the gate insulating film is not deteriorated.
[0036]
  From the above, in order to achieve both suppression of interfacial oxide film thickness increase and suppression of silicidation
In a high temperature heat treatment process atmosphere exceeding 650 ° C.At least one of He or NeIt is effective to add the gas and control the partial pressure of the oxidizing species in the atmosphere according to the heat treatment temperature.
[0037]
In this example, the results when 100% He gas was used for the heat treatment were mainly shown, but the same improvement effect was confirmed with Ne, Ar having a smaller atomic radius than nitrogen atoms, and mixed gases thereof. .
[0038]
The rare gas used in the first production method of the present invention and the second production method described later is most preferably He gas, and then Ne is most desirable for obtaining the effects of the invention. Even if these rare gases are diluted with nitrogen gas or a rare gas having a larger atomic radius than nitrogen atoms (Kr, Xe, etc.), the effect is maintained. In addition, the rare gas partial pressure during the heat treatment may be reduced pressure or normal pressure, and further effects can be obtained by increasing the pressure. Specifically, the pressure is desirably 1.33 Pa or more and 1010800 Pa or less. A particularly desirable rare gas partial pressure is desirably 133 Pa or more and 13300 Pa or less in order to ensure the purity of the rare gas.
[0039]
In the first manufacturing method and the second manufacturing method of the present invention, the high dielectric constant metal oxide insulating film is formed by a metal insulating film formed by ALCVD (Atomic Layer CVD), vapor deposition, plasma CVD or the like in addition to sputtering. Even if it is a film | membrane, the same effect can be acquired.
(Second embodiment)
The second manufacturing method of the present invention will be described by taking MIS transistor formation as an example.
Since the element structure of the MIS transistor according to the second embodiment is the same as that of the first embodiment, detailed description thereof is omitted.
[0040]
In this example, the first step, the third step, the fourth step to the fifth step, and the seventh step were performed in the same manner as in the first example, but the high dielectric constant metal oxide film in the second step was used. Only the formation step and the activation heat treatment step, which is the sixth step, differ from the first embodiment. Therefore, the second process will be described with reference to FIG. 2, and the activation heat treatment process, which is the sixth process, will be described with reference to FIG.
[0041]
The second step is ZrO after film formation₂This was performed in the same manner as in the second step of the first embodiment, except that heat treatment for densification of the film 14 and defect reduction was not performed.
[0042]
In the activation heat treatment step, arsenic ions are implanted into the first gate electrode 15 by, for example, an acceleration voltage of 40 keV and a dose amount of 2 × 10.¹⁵cm^-2By performing the activation heat treatment under the conditions of n, high impurity concentration n⁺Type gate electrode 15, n⁺Type source region 17, n⁺A type drain region 18 was formed at the same time.
[0043]
  The activation heat treatment conditions at this time are shown below.
  <Ne atmosphere>
  Background vacuum: 133 * 1E-7Pa
  Ne pressure: 1 atm
  Sum of oxygen and moisture pressure in the atmosphere: 133 * 1E-6Pa
  Substrate temperature: 1000 ° C
  Heating time: 10 seconds
  This heat treatment condition corresponds to the reduction region in FIG. 8 according to the first embodiment, and the poly-Si gate functions as a cap layer, that is, a diffusion block of oxidizing species. Therefore, in the normal UHV or N2 heat treatment, Due to this reaction, silicide is formed at the poly-Si / ZrO2 interface. However, by performing the heat treatment in the presence of a rare gas, such as the Ne heat treatment of the present embodiment, silicidation at the interface is suppressed by the same operation as that of the first manufacturing method of the present invention described in the first embodiment, Increase in roughness can be suppressed. Furthermore, in the first manufacturing method of the present invention, in order to prevent an increase in the SiO2 oxide film at the interface, the partial pressure of the oxidizing species in the heat treatment atmosphere is 133 * 1011.703-18114 / TPa is the heat treatment temperature (K). However, in the second manufacturing method, since the increase in SiO2 is suppressed by the presence of the thin film serving as the cap layer, it is not necessary to control within the above range. However, desirably, the partial pressure of the oxidizing species is 133 * 10.^{11.703-18114 / T}Pa (T is the heat treatment temperature (K)) or less, more preferably the partial pressure of the oxidizing species133 * 10 ^{8.903-18114 / T} PaIn order to obtain the effects of the present invention, (T is the heat treatment temperature (K)) or less is desirable.
[0044]
The thin film provided on the metal oxide insulating film to be the cap layer may also serve as the gate electrode as in this embodiment, or may be provided separately from the gate electrode. The thin film is effective not only for poly-Si but also for materials used for all gate electrodes containing Si atoms such as poly-SiGe. The thickness of the thin film is preferably in the range of 5 nm to 500 nm.
[0045]
In this example, the results obtained when 100% Ne gas was used for the heat treatment were mainly shown, but the same improvement effect was confirmed with He, Ar having a smaller atomic radius than nitrogen atoms, and mixed gases thereof. .
[0046]
In this embodiment, ZrO is mainly used.₂Although described with respect to the membrane, HfO₂The same improvement effect has been confirmed for the film.
[0047]
In the second manufacturing method of the present invention, it has been clarified that the maximum effect is exhibited by setting the heat treatment temperature to 650 ° C. or higher for the same reason as in the first manufacturing method. On the other hand, the upper limit of the heat treatment temperature is not particularly limited, but ZrO₂It is desirable that the temperature is 1200 ° C. or lower at which the film does not deteriorate. More preferably, it is 1050 degrees C or less.
[0049]
FIG. 10 shows ZrO before and after the activation heat treatment in the second embodiment.₂/ SiO₂The change in the distribution of Ne atoms in the depth direction in the laminated film was examined using secondary ion mass spectrometry (hereinafter referred to as SIMS). Compared with before heat treatment, it is confirmed that Ne is present in the film, and it is found that the film is distributed almost uniformly in the bulk.
[0050]
Similarly, in the manufacturing method of the first embodiment, it was confirmed separately that He was present in the film.
[0051]
By containing He atoms in the high dielectric constant metal oxide insulating film in this manner, stress in the film, the substrate interface, and the interface with the gate electrode is relieved and thermal vibration of the bond is reduced to 0. Due to the cooling effect of the group element, the charge in the film and the interface state density are reduced, and a gate insulating film having a high dielectric constant and a small leakage current can be obtained. Actually, when the leakage current of the MIS capacitor subjected to He annealing was measured, it was found that the leakage current was reduced by about an order of magnitude or more compared to the case of N 2 annealing, and the transistor of the present invention has excellent characteristics.
[0052]
BookExampleExamples of the group 0 element contained in the high dielectric constant metal oxide insulating film used as the gate insulating film in the semiconductor device are He, Ne, and Ar. He is the most effective from the viewpoint of cooling efficiency (thermal conductivity). Preferred is Ne next.
[0053]
The concentration of the group 0 element contained in the high dielectric constant metal oxide insulating film is 1E.¹⁷atoms / cm^Three1E^{twenty one}atoms / cm^ThreeThe following ranges are desirable because they do not involve film structure changes.
[0054]
【The invention's effect】
As described above, according to the present invention, SiO at the metal oxide insulating film / Si substrate interface is used.₂The increase in the film and the formation of silicide at the gate electrode / metal oxide insulating film interface and the metal oxide insulating film / Si substrate interface are suppressed, and the gate electrode / metal oxide insulating film and metal oxide insulating film / Si substrate interface are suppressed. It is possible to achieve both a reduction in roughness and suppression of a decrease in dielectric constant of a high dielectric constant metal oxide insulating film, and a semiconductor device having a highly reliable insulating film with little leakage current can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a manufacturing process of an n-type MOS transistor according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a manufacturing process of an n-type MOS transistor according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a manufacturing process of an n-type MOS transistor according to an embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a manufacturing process of an n-type MOS transistor according to an embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a manufacturing process of an n-type MOS transistor according to an embodiment of the present invention.
FIG. 6 is a cross-sectional view showing a manufacturing process of an n-type MOS transistor according to an embodiment of the present invention.
FIG. 7 shows changes in Zr3d and Si2p spectra under various heat treatment conditions according to the first embodiment of the present invention.
FIG. 8 is a characteristic diagram showing oxidation / reduction boundaries of partial pressure of oxidizing species with respect to various heat treatment temperatures according to the first embodiment of the present invention.
FIG. 9 is an explanatory view of the operation according to the first embodiment of the present invention.
FIG. 10 shows ZrO according to a second embodiment of the present invention.₂/ SiO₂Depth distribution of Ne atoms in the laminated film.
[Explanation of symbols]
11 p-type silicon substrate
12 Element isolation groove
13 Silicon oxide film (element isolation region)
14 ZrO₂film
15 Polysilicon film
16 photoresist pattern
17 n⁺Type source area
18 n⁺Type drain region
19 Silicon oxide film (interlayer insulation film)
110 Source electrode (metal electrode)
111 Drain electrode (metal electrode)
112 Gate electrode (metal electrode)

Claims (4)

Forming a high dielectric constant metal oxide film on a silicon substrate;
After the high dielectric constant metal oxide film formation step, the sum of partial pressures of oxygen and water is 133 * 10 ^{11.703-18114 / T} Pa (T is the heat treatment) with the high dielectric constant metal oxide film exposed. A step of performing a heat treatment at 650 ° C. or higher in an atmosphere in which a gas that is at least one of He or Ne is present,
A method of manufacturing a semiconductor device having a high dielectric constant metal oxide film, comprising a step of forming an MIS transistor using the high dielectric constant metal oxide film. The sum of the partial pressures of oxygen and water contained in the atmosphere of the heat treatment step is 133 * 10 ^{8.903-18114 / T} Pa (T is the heat treatment temperature (K)) or less. Semiconductor device manufacturing method. Forming a high dielectric constant metal oxide film on a silicon substrate;
Forming a thin film on the high dielectric constant metal oxide film;
Patterning the thin film;
After the step of patterning the thin film, the partial pressure of oxygen and water is 133 * 10 ^{11.703-18114 / T} Pa where T is the heat treatment temperature (K) with the high dielectric constant metal oxide film exposed. A step of performing a heat treatment at 650 ° C. or higher in an atmosphere in which a gas that is at least one of He or Ne is present;
A method of manufacturing a semiconductor device having a high dielectric constant metal oxide film, comprising a step of forming an MIS transistor using the high dielectric constant metal oxide film. 4. The sum of partial pressures of oxygen and water contained in the atmosphere of the heat treatment step is 133 * 10 ^{8.903-18114 / T} Pa (T is the heat treatment temperature (K)) or less. Semiconductor device manufacturing method.

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