JP4868910B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a semiconductor device having an insulating film having a stacked structure of an adsorption layer in which a metal element is adsorbed on the surface of a semiconductor substrate and a high dielectric film, and a method for manufacturing the same.

ULSI (Ultra Large Scale Integration) has been promoting high speed and low power consumption by miniaturization of MISFET (Metal Insulator Semiconductor Field Effect Transistor) which is the main element. By reducing the thickness of the gate insulating film, which can be said to be the heart of MISFET, the electrostatic capacity (hereinafter also referred to as gate capacity) is increased, and the performance of MISFET has been improved. However, the silicon oxide film (SiO ₂ ) that has been used so far has been reduced to a few nanometers in recent years, causing leakage current due to direct tunneling current. There is a problem that makes it difficult. In order to further increase the gate capacitance while suppressing this direct tunnel current, it is necessary to use a high dielectric (high-k) film, which is an insulating film having a dielectric constant higher than that of SiO ₂ .

Until now, strontium titanate (SrTiO ₃ (hereinafter also referred to as STO)), cerium oxide (CeO ₂ ), tantalum oxide (Ta ₂ O ₅ ), titanium oxide (TiO ₂ ), and zirconium oxide have been proposed as candidates for high dielectric films. Various materials such as oxides such as (ZrO ₂ ) and hafnium oxide (HfO ₂ ), oxynitrides in which the above oxide and nitrogen are mixed, and silicates in which Si is mixed have been studied. However, when a high dielectric film is formed on a Si substrate, most of it is an oxide. Therefore, a low dielectric constant interface reaction layer such as a SiO ₂ film or a silicate film is formed at the interface between the Si substrate and the high dielectric film. Cheap. As a result, there arises a problem that the gate capacitance is reduced due to the series capacitance of the high dielectric film and the interface reaction layer. It has also been reported that even if a high dielectric film can be directly bonded to a Si substrate, a large amount of defects are formed at the interface and the interface state is likely to increase (for example, see Non-Patent Document 1). The interface state must be reduced as much as possible in order to scatter carriers flowing through the channel of the MISFET and prevent mobility from being lowered, that is, speeding up of the MOSFET.

From the above, in order to apply the high dielectric film to the gate insulating film of MISFET, a) suppressing the interface reaction layer;
b) suppressing interface defects and reducing interface states;
Is important.

In order to realize the above a) and b), a method of inserting a metal adsorption layer at the interface between the Si substrate and the high dielectric film has been proposed. This is a method to reduce the interface state while suppressing the formation of the interface reaction layer such as SiO ₂ film or silicate film by terminating the bond at the Si interface (hereinafter dangling bond) with the metal adsorption layer. There is a proposal like this.

RA Mckee et al. Have proposed a method of forming an adsorption layer of strontium (Sr) as a metal element at the interface between a Si (100) substrate and a high dielectric film (see, for example, Non-Patent Documents 2 and 3). The adsorption layer is formed by supplying 1/4 ML of Sr at a substrate temperature of 600 ° C., and subsequently supplying 3/8 ML at a substrate temperature of 150 ° C. Here, ML represents a monolayer, which corresponds to 1ML = 6.8 × 10 ⁻¹⁴ pieces / cm ² . The high dielectric film has succeeded in suppressing the interfacial reaction layer by using a laminated film of an STO film and barium strontium oxide (BaSrO).

However, the value of the interface state of the conventionally used SiO ₂ film is lower than 1 × 10 ¹¹ eVcm ⁻² , whereas the interface state by this adsorption layer is 1 × 10 ¹² eV ⁻ immediately after the film formation. ^Even if forming gas annealing is performed at ¹ cm ⁻² , it can be reduced only to about 1.3 × 10 ¹¹ eV ⁻¹ cm ⁻² . In order to completely terminate the dangling bond on the surface of the Si substrate with divalent Sr, 1/2 ML is required. However, since a total of 5/8 ML of Sr was supplied, 1/8 ML of Sr was excessive, and the interface state It is thought that the position could not be reduced.

  Y. Liang et al. Proposed a method of forming an adsorption layer having a Sr / Si (100) 2 × 1 structure by supplying 1/2 ML of Sr to a Si (100) substrate (see, for example, Non-Patent Document 4). . However, Sr silicate is formed by exposing their Sr adsorption layer to an oxygen atmosphere. As they describe, when Sr increases or decreases slightly even than 1/2 ML, the Si substrate is oxidized without terminating the dangling bonds completely, or Sr / Si (100) 2 is supplied due to excessive supply of Sr. This is probably because an unstable structure that is easily silicated other than the × 1 structure was locally formed.

  Shimizu et al. Have proposed a method of forming 1 ML of non-metal silicide (see, for example, Patent Document 1). A specific method is to stabilize the silicide by supplying a metal element to the Si surface and heating it as necessary to reduce the interface state. However, for example, S.M. According to a report by Hu et al., There are cases where two structures of 2 × 1 structure and n × 2 structure are formed with 1 ML of Sr silicide (see, for example, Non-Patent Document 5). When a structure other than 2 × 1 is formed, oxidation resistance is lost and silicate formation occurs, as reported by Y. Liang et al., That is, an interface reaction layer may be formed (for example, non-patent Reference 4).

Like Y. Liang, H. Li and others have succeeded in forming a Sr / Si (100) 2 × 1 structure, which is an Sr adsorption layer, and directly bonding a high dielectric STO film to a Si substrate. (For example, refer nonpatent literature 6). However, even if the Sr adsorption layer can be formed, it has been reported that a silicate layer is formed unless the deposition temperature and oxygen partial pressure of the STO film are controlled. That is, in order to suppress the interface reaction layer, it is necessary to form a high dielectric film at as low a temperature and a low oxygen partial pressure as possible. The film formation at a low temperature and a low oxygen partial pressure generally has a problem that oxygen deficiency is easily introduced into the high dielectric film and the insulating property is likely to deteriorate.
Y. Nishikawa, T. Yamaguchi, M. Yoshiki, H. Satake, and N. Fukushima, Appl. Phys. Lett. 81, 4386 (2002) S. Jeon, FJ Walker, CA Billman, RA Mckee and H. Hwang, IEDM Tech.Dig.p955 (2002) RA Mckee, FJ Walker and MF Chisholm, Phys. Rev. Lett. 81, 3014 (1998) Y. Liang, S. Gan, and M. Engelhard, Appl. Phys. Lett. 79, 3591 (2001) JP 2005-294564 A H. Li, X. Hu, Y. Wei, Z. Yu, X, Zhang, R. Droopad, AA Demkov, J. Edwards, Jr., K. Moore, W. Ooms, J. Kulik and P. Fejes, Appl. Phys. Lett. 93, 4521 (2003) X. Hu, Z. Yu, JA Curless, R. Droopad, K. Eisenbeiser, JL Edwards Jr., WJ Ooms, D. Sarid, Appl. Surf. Sci. 181, 103 (2001)

  So far, a method has been described in which Sr is supplied to a Si substrate to form an Sr / Si (100) 2 × 1 adsorption layer, thereby suppressing an interfacial reaction layer that is likely to be formed at the Si dielectric interface. It was.

  As can be seen from the above, it has been clarified that it is necessary to devise a dielectric film formed on the adsorption layer so that a structure other than the Sr / Si (100) 2 × 1 structure is not formed. .

  The present invention has been made in consideration of the above circumstances, and can suppress the formation of an interface reaction layer that is likely to be formed at the interface between a high dielectric film and a semiconductor substrate, and can reduce the interface state. An object is to provide an apparatus and a method for manufacturing the same.

A semiconductor device according to a first aspect of the present invention includes a single crystal semiconductor substrate, a metal element adsorbed on the single crystal semiconductor substrate, and a single periodic structure aligned with an atomic arrangement on the surface of the single crystal semiconductor substrate. An adsorption layer, a dielectric film formed on the adsorption layer, and an electrode formed on the dielectric film, an oxide of a metal element constituting the adsorption layer, and an element of the single crystal semiconductor substrate And ΔH _a ≧ ΔH _d and ΔH _s ≧ ΔH, where ΔH _a , ΔH _s , and ΔH _d are the standard generation enthalpies per unit oxygen of the oxide of the metal element and the oxide of the metal element constituting the dielectric film, respectively. _The adsorption layer and the dielectric film are formed of a metal element satisfying the relationship _d .

The adsorption layer includes at least one element selected from Al, Mg, Ca, Sr, Ba, Ra, Ti, Zr, and Hf, and the dielectric film includes Al ₂ O ₃ or LnAlO ₃ (where, Ln may be any one of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu).

The adsorption layer includes at least one element selected from Ti, Ba, Ra, Zr, and Hf, and the dielectric film includes Zr ₂ Hf ₂ O ₇ , Hf ₂ Al ₂ O ₇ , and Ln ₂ Hf ₂ O. ₇ (wherein Ln is any one of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu).

The adsorption layer includes at least one element selected from Ti, Ba, Ra, and Zr, and the dielectric film includes ZrO ₂ , Zr ₂ Al ₂ O _7, and Ln ₂ Zr ₂ O ₇ (where Ln is Any one of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu).

  The metal element constituting the adsorption layer may be at least one selected from Mg, Ca, Sr, Ba, and Ra, and the surface density thereof may be ½ of the surface density of atoms on the surface of the semiconductor substrate.

If the unit cells of the unit cell of the cross-sectional structure of the semiconductor substrate are → a ₁ , → a ₂ , the unit cell of the periodic structure of the adsorption layer is 2 × → a ₁ , 2 × → a ₂ as a unit vector. There may be.

  According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: supplying a metal element to a surface of a single crystal semiconductor substrate; and heating the single crystal semiconductor substrate to arrange an atomic arrangement on the surface of the single crystal semiconductor substrate. A step of forming an adsorption layer having a single atomic arrangement consistent with the step of: forming a dielectric film on the adsorption layer; and forming a gate electrode on the dielectric film. It is characterized by.

  The metal element is Sr, and the single atomic arrangement in the adsorption layer has a Sr / Si (100) 2 × 1 structure, and the step of forming the adsorption layer is performed at a heating temperature of 650 ° C. or higher and 850 ° C. A step of detaching the excessively supplied Sr from the semiconductor substrate may be provided by setting the temperature to not higher than ° C.

The step of forming the dielectric film may be performed in an atmosphere having a substrate temperature of 200 ° C. to 700 ° C. and an oxygen partial pressure of 1 × 10 ⁻⁸ torr to 1 × 10 ⁻⁶ torr.

  According to the present invention, it is possible to reduce the interface state while suppressing the formation of an interface reaction layer that is easily formed at the interface between the high dielectric film and the semiconductor substrate.

  Embodiments of the present invention will be described below with reference to the drawings. In this description, common parts are denoted by common reference numerals throughout the drawings.

As a result of earnestly examining the conventional technology, the present inventors have suppressed the formation of the interface reaction layer and reduced the interface state.
a) Suppressing the formation of an interface reaction layer by forming an adsorption layer of a metal element having a single periodic structure at the interface between the semiconductor substrate and the dielectric film,
b) We thought that it was necessary to select a dielectric material that hardly forms oxygen vacancies under film-forming conditions that can maintain the oxidation resistance of the adsorption layer and to use it for the gate insulating film.

  Therefore, in the following embodiment, description will be made as an example in which the above a) and b) are realized.

  A schematic cross section of a MISFET according to an embodiment of the present invention is shown in FIG. As shown in FIG. 1, the MISFET of this embodiment includes an adsorption layer 2 that adsorbs a metal element formed on a semiconductor substrate 1 made of single crystal Si, and a dielectric film 3 formed on the adsorption layer 2. And a gate electrode 4 formed on the dielectric film 3 and source / drain regions 5 formed on the semiconductor substrate 1 on both sides of the gate electrode 4.

The adsorption layer 2 is “matched” with the atomic arrangement on the surface of the single crystal semiconductor substrate 1 and has a single atomic arrangement. As a result, the dangling bond of the semiconductor substrate 1 is terminated, and the interface state can be reduced while the oxidation of the semiconductor substrate 1 is suppressed. The basic vectors of the two-dimensional Brave lattice on the ideal surface of the semiconductor substrate are set as → e ₁ and → e _2, and the basic vectors of the two-dimensional Brave lattice of the adsorption layer are set as → a ₁ and → a ₂ . Here, for example, the symbol “→ e ₁ ” indicates that an arrow → is attached on e ₁ . Then, what is “consistency”?
The determinant of the matrix M expressed by is a rational number. Further, the structure of the adsorption layer 2 will be expressed as an A / M (100) m × n structure in the following using the Wood notation. In this notation method, the element A is adsorbed on the (100) substrate surface of the single crystal semiconductor substrate of the element of the matrix M to form an adsorption layer, and the basic vector of the two-dimensional Brave lattice on the ideal surface is the adsorption layer. Is a structure having basic vectors of m × (→ e ₁ ) and n × (→ e ₂ ), where is set to → e ₁ , → e ₂ . For example, the hydrogen termination surface formed by hydrofluoric acid treatment of a Si (100) single crystal substrate has the same period as the ideal surface of the Si substrate, and is therefore expressed as an H / Si (100) 1 × 1 structure. .

  In the present embodiment, the dielectric film 3 is composed of an oxide unit oxygen in the oxide of the metal element constituting the high dielectric film 3 rather than the oxide of the metal element constituting the adsorption layer 2 or the element of the semiconductor substrate. Suppose that the standard generation enthalpy in hit is the same or small The standard enthalpy of production indicates the amount of heat necessary for oxidation and reduction of the oxide, and the smaller value of the oxide indicates that it is easier to oxidize and less likely to be reduced. That is, in the present embodiment, the dielectric film 3 is an oxide composed of an element that is more easily oxidized than the adsorbing element of the semiconductor substrate 1 or the adsorption layer 2. As a result, oxygen deficiency is formed even if the film is formed in an oxygen atmosphere where the temperature of the semiconductor substrate 1 and the adsorption layer 2 can maintain the oxidation resistance of the surface, for example, the temperature of the semiconductor substrate is low and the oxygen partial pressure is low. Insulating properties can be maintained.

  As described above, the semiconductor device of this embodiment can reduce the interface state while suppressing the formation of the interface reaction layer that is easily formed at the interface between the high dielectric film and the semiconductor substrate. Thereby, a MISFET capable of low power consumption and high speed operation can be obtained.

  Next, the method for fabricating the semiconductor device according to the present embodiment will be explained. As shown in FIG. 1, the MISFET of this embodiment has a laminated structure of an adsorption layer 2 and a high dielectric film 3 as a gate insulating film, but the configuration other than the gate insulating film is a general MISFET. It was the same structure. For this reason, in the manufacturing process of the following manufacturing method, only the formation method of the gate insulating film on the Si substrate will be described.

  First, a method for forming the adsorption layer will be described, and then a case where a high dielectric film is formed on the adsorption layer will be described.

(Adsorption layer forming method 1)
As a first example of the method for forming the adsorption layer, a method for forming an adsorption layer having an Sr / Si (100) 2 × 1 structure using Sr as the metal element will be described. The Sr supply method was a molecular beam epitaxy method (MBE (Molecular Beam Epitaxy) method). A film forming process of the Sr / Si (100) 2 × 1 structure will be described with reference to FIGS. 2 (a) to 3 (b).

First, the p-type Si (100) substrate 1 is treated with hydrofluoric acid to terminate dangling bonds on the outermost surface with hydrogen (FIG. 2A). (FIG. 2 (a)). Next, by introducing the substrate 1 into a film formation chamber having an ultimate vacuum of 5 × 10 ⁻¹⁰ torr and heating at 400 ° C. or more and 600 ° C. or less, the terminated hydrogen 10 is desorbed from the Si substrate 1 and Si (100 ) A 2 × 1 structure 12 is formed (FIG. 2B). The Si (100) 2 × 1 structure 12 is a structure in which dangling bonds of two adjacent Si atoms on the outermost surface are covalently bonded to form a dimer, and a schematic view seen from the upper part of the Si (100) substrate is shown in FIG. Shown in

Next, 1/2 to 10 mL of Sr is supplied to the surface of the Si (100) 2 × 1 structure 12 using a Knudsen cell (hereinafter referred to as k cell) which is an evaporation source of Sr metal (FIG. 2C). By supplying Sr of 1/2 ML or more, the surface of the Si (100) 2 × 1 structure 12 can be entirely covered with Sr. Next, the metal (Sr) 14a supplied excessively is desorbed from the Si substrate by heating at a temperature higher than 650 ° C. and lower than the temperature at which the Si surface can be melted (1212 ° C.) (FIG. 3A). The adsorption layer 2 having a Sr / Si (100) 2 × 1 structure composed of 1/2 ML of Sr can be formed (FIG. 3B). That is, since the metal element Sr constituting the adsorption layer is 1/2 ML, its surface density is 3.4 × 10 ⁻¹⁴ atoms / cm ² , which is 1/2 of the surface density of Si on the surface of the semiconductor substrate. It becomes. FIG. 5 shows a schematic view of the Sr / Si (100) 2 × 1 structure 2 as viewed from above the substrate. In addition, FIG. 6 shows a temperature program for the film forming method.

  It was confirmed by RHEED (Reflection High Energy Electron Diffraction), STM (Scanning Tunneling Microscopy), etc. that it is a single structure of only Sr / Si (100) 2 × 1 structure. In addition, after removal from the deposition chamber, the amount of Sr can be confirmed by ICP-AES analysis (Inductively Coupled Plasma Atomic Emission Spectrometry). Can be confirmed by taking a HAADF (High Angle Annular Dark Field) image by transmission electron microscopy.

  In the background art, Y. Liang et al. Described that the Sr / Si (100) 2 × 1 structure is formed, but the silicate layer is easily formed because other structures are formed (Non-patent Document 4, Patent Document). 1). In their method, the amount of Sr needs to be exactly ½ ML, so it was difficult to form a single structure.

  However, in this embodiment, the amount of Sr that can sufficiently cover the entire surface of the Si (100) substrate is supplied at a low temperature, and the Sr that is supplied in excess of 1/2 ML is desorbed from the Si substrate by subsequent heating. A self-aligned Sr adsorption layer can be formed. Further, a stable Sr / Si (100) 2 × 1 single structure can be formed that can suppress an interface reaction layer that is likely to be formed at the interface with a high dielectric film to be formed later.

(Adsorption layer forming method 2)
Next, as a second example of the method for forming the adsorption layer, a method for forming an adsorption layer having a Ba / Si (100) 2 × 1 structure using Ba as the metal element of the adsorption layer will be described. An electron beam evaporation method is used as a method of forming the Ba / Si (100) 2 × 1 structure.

First, a p-type Si (100) substrate in which dangling bonds on the outermost surface are hydrogen-terminated by hydrofluoric acid treatment is introduced into a film formation chamber having an ultimate vacuum of 5 × 10 ⁻¹⁰ torr. Subsequently, the terminal hydrogen is desorbed from the Si substrate by heating the Si substrate at 400 ° C. or more and 700 ° C. or less to form a Si (100) 2 × 1 structure.

Next, Ba metal is supplied to this structure by electron beam evaporation, and ½ to 10 ML is supplied to the surface of the Si (100) 2 × 1 structure. This Ba amount is an amount covering the entire surface of the Si (100) substrate. Subsequently, a Ba / Si (100) 2 × 1 structure can be formed by raising the substrate temperature to 700 ° C. to 900 ° C. Also in this case, since the metal element Ba constituting the adsorption layer is 1/2 ML, the surface density thereof is 3.4 × 10 ⁻¹⁴ atoms / cm ² , which is 1 of the surface density of Si on the surface of the semiconductor substrate. / 2.

  As described above, Ba is an alkaline earth metal and has the same adsorption structure, so that the formation method is almost the same.

In the above embodiment, the Sr / Si (100) 2 × 1 structure or the Ba / Si (100) 2 × 1 structure is used as the adsorption layer, but Mg, Ca, and Ra are similarly adsorbed by 1/2 ML to form Si. (100) Dangling bonds on the surface can be terminated. Mg, Ca, and Ra can also form a stable adsorption layer having a 2 × 1 structure on the Si (100) surface. Also in this case, since the metal element constituting the adsorption layer is 1/2 ML, the surface density thereof is 3.4 × 10 ⁻¹⁴ atoms / cm ² , which is 1 / of the surface density of Si on the surface of the semiconductor substrate. 2.

  This time, the adsorption layer was formed using the MBE method and the electron beam evaporation method. Appendices.

(Example 1 of forming high dielectric film on adsorption layer)
An example in which a lanthanum aluminate film (LaAlO ₃ : LAO) is used as the high dielectric film on the adsorption layer and the Sr / Si (100) 2 × 1 structure is used as the adsorption layer will be described. Since the LAO film has a standard enthalpy value per unit oxygen of La ₂ O ₃ and Al ₂ O ₃ smaller than that of SrO or SiO ₂ , the LAO film can be oxygenated even in a low temperature or low oxygen partial pressure oxygen atmosphere. Defects are hardly formed and good insulation can be maintained. The LAO film was formed by the MBE method similarly to the Sr adsorption layer. A method for forming the LAO film will be described below. After forming the Si (100) 2 × 1 structure, the substrate temperature is set to 200 ° C. to 700 ° C., and La and Al are oxygen partial pressures of 1 × using k-cells of lanthanum metal (La) and aluminum metal (Al). An LAO film can be formed by supplying in an oxygen atmosphere of 10 ⁻⁸ torr to 1 × 10 ⁻⁶ torr. The film thickness of the LAO film was 2.8 nm, and finally a molybdenum electrode (Mo) was formed by electron beam evaporation. As a result of capacitance-voltage measurement (CV measurement) between the gate electrode and the Si substrate, the equivalent oxide thickness (EOT) estimated from the CV characteristics is 0.5 nm. I was able to form. Further, when the MISFET was fabricated and the interface state was measured, it could be reduced to 9.0 × 10 ⁹ eV ⁻¹ cm ⁻² and SiO _2, and a high mobility MISFET could be formed. In addition, it was confirmed by cross-sectional TEM observation that there was no interface reaction layer, and the presence of a Sr / Si (100) 2 × 1 structure could be confirmed in the TEM / HAADF image.

  In the above, the MBE method is used for forming the LAO film. However, the LAO film can also be formed by using the sputtering method, the electron beam evaporation method, the laser ablation method, or the like as in the case of the adsorption layer.

(Example 2 of forming high dielectric film on adsorption layer)
Next, an example using a Ba / Si (100) 2 × 1 structure as the adsorption layer 2 and hafnium aluminate (HfAlON) as the high dielectric film 3 is shown. First, after forming an adsorption layer having a Ba / Si (100) 2 × 1 structure on a Si substrate, the substrate temperature was set to 200 ° C. or more and 700 ° C. or less, and a 1: 1 mixed gas of N ₂ and O ₂ (total Pressure: 1 × 10 ⁻⁸ torr to 1 × 10 ⁻⁶ torr) was introduced into the deposition chamber. Next, an HfAlON film was formed on the Si substrate by sputtering an HfAlO target using a 3 kW sputtering gun. It was confirmed that the interface reaction layer was suppressed by forming a 2.5 nm HfAlON film and performing cross-sectional TEM observation after removing the Si substrate from the deposition chamber. As a result of carrying out CV measurement after forming a Mo electrode by electron beam evaporation on this film, an estimated oxide equivalent film thickness (EOT) of 0.6 nm could be formed. Further, the interface state could be reduced to 8.7 × 10 ⁻⁹ cm ⁻² . When a MISFET using the gate insulating film formed by this method was formed, a high-speed MISFET having very high mobility could be formed.

(Comparative Example 1)
As Comparative Example 1, an Sr / Si (100) 2 × 1 structure is used as the adsorption layer, and a TiO ₂ film is used as the high dielectric film. The MBE method was used for forming the TiO ₂ film. The Sr / Si (100) 2 × 1 structure is formed using the same method as shown in Method 1 for forming the adsorption layer. The TiO ₂ film in the following 400 ° C. substrate temperature of 200 ° C. or higher, titanium (Ti) by using the evaporation source of the metal 1 × ¹⁰ -8 ~1 × of ¹⁰ -6 torr of TiO ₂ film in an oxygen atmosphere Sr / Si ( 100) A 11.2 nm film was formed on a 2 × 1 structure.

In the comparative example thus formed, it was confirmed that the interface reaction layer was suppressed by TEM cross-sectional observation. However, when current-voltage measurement (IV measurement) was performed, the formed TiO ₂ film had a very large leakage current and did not exhibit good insulation. The TiO ₂ film has a small standard generation enthalpy per unit oxygen, and is not sufficiently oxidized under this film formation condition, which is considered to be an insulation failure.

(Selection of combination of adsorption layer with high dielectric film)
In the above example, two examples of the formation of the adsorption layer and two examples of the formation of the high-dielectric film are illustrated, but the combination of the metal element and the dielectric film of the adsorption layer shows a list of standard generation enthalpies. 7 can be determined as follows.

Al ₂ O ₃ or Ln ₂ O ₃ , LnAlO ₃ (Ln = Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) was used for the dielectric film. In this case, the adsorption layer can be selected from Al, Mg, Ca, Sr, Ba, Ra, Ti, Zr, and Hf.

In addition, ZrO ₂ or Zr ₂ Al ₂ O ₇ or Ln ₂ Zr ₂ O ₇ (Ln = Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb , Lu), Ti, Ba, Ra, Zr can be selected as the adsorption layer.

Further, Zr ₂ Hf ₂ O ₇ or Hf ₂ Al ₂ O ₇ or Ln ₂ Hf ₂ O ₇ (Ln = Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er , Tm, Yb, Lu), Ti, Ba, Ra, Zr, and Hf can be selected as the adsorption layer.

1 is a cross-sectional view showing a MISFET according to an embodiment of the present invention. Sectional drawing which shows the manufacturing method of the semiconductor device by one Embodiment of this invention. Sectional drawing which shows the manufacturing method of the semiconductor device by one Embodiment of this invention. The schematic diagram seen from the Si (100) substrate upper part at the time of the dangling bond of two adjacent Si atoms of the outermost surface of a Si (100) 2x1 structure being covalently bonded, and forming a dimer. The schematic diagram which looked at Sr / Si (100) 2x1 structure 2 from the upper part of a substrate. The figure which shows the temperature program of the film-forming method 1 of an adsorption layer. The figure which shows the standard production | generation enthalpy of a metal oxide and a dielectric material, and the standard production | generation enthalpy per unit oxygen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Single crystal semiconductor substrate 2 Adsorption layer 3 Dielectric film 4 Electrode 5 Source / drain

Claims (8)

A single crystal semiconductor substrate;
An adsorption layer containing a metal element adsorbed on the single crystal semiconductor substrate and having a single periodic structure aligned with an atomic arrangement on the surface of the single crystal semiconductor substrate;
A dielectric film formed on the adsorption layer;
An electrode formed on the dielectric film,
The standard generation enthalpies per unit oxygen of the oxide of the metal element constituting the adsorption layer, the oxide of the element of the single crystal semiconductor substrate, and the oxide of the metal element constituting the dielectric film are respectively ΔH _a , When ΔH _s and ΔH _d , the adsorption layer and the dielectric film are formed of a metal element that satisfies the relationship of ΔH _a ≧ ΔH _d and ΔH _s ≧ ΔH _d ,
The adsorption layer includes at least one element selected from Al, Mg, Ca, Sr, Ba, Ra, Ti, Zr, and Hf, and the dielectric film includes Al ₂ O ₃ or LnAlO ₃ (where Ln is , Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). A single crystal semiconductor substrate;
An adsorption layer containing a metal element adsorbed on the single crystal semiconductor substrate and having a single periodic structure aligned with an atomic arrangement on the surface of the single crystal semiconductor substrate;
A dielectric film formed on the adsorption layer;
An electrode formed on the dielectric film,
The standard generation enthalpies per unit oxygen of the oxide of the metal element constituting the adsorption layer, the oxide of the element of the single crystal semiconductor substrate, and the oxide of the metal element constituting the dielectric film are respectively ΔH _a , When ΔH _s and ΔH _d , the adsorption layer and the dielectric film are formed of a metal element that satisfies the relationship of ΔH _a ≧ ΔH _d and ΔH _s ≧ ΔH _d ,
The adsorption layer includes at least one element selected from Ti, Ba, Ra, Zr, and Hf, and the dielectric film includes Zr ₂ Hf ₂ O ₇ , Hf ₂ Al ₂ O ₇ , and Ln ₂ Hf ₂ O ₇ ( Here, Ln is any one of Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). . A single crystal semiconductor substrate;
An adsorption layer containing a metal element adsorbed on the single crystal semiconductor substrate and having a single periodic structure aligned with an atomic arrangement on the surface of the single crystal semiconductor substrate;
A dielectric film formed on the adsorption layer;
An electrode formed on the dielectric film,
The standard generation enthalpies per unit oxygen of the oxide of the metal element constituting the adsorption layer, the oxide of the element of the single crystal semiconductor substrate, and the oxide of the metal element constituting the dielectric film are respectively ΔH _a , When ΔH _s and ΔH _d , the adsorption layer and the dielectric film are formed of a metal element that satisfies the relationship of ΔH _a ≧ ΔH _d and ΔH _s ≧ ΔH _d ,
The semiconductor element is characterized in that at least one metal element constituting the adsorption layer is selected from Mg, Ca, Sr, Ba, and Ra, and the surface density thereof is ½ of the surface density of atoms on the surface of the semiconductor substrate. apparatus. A single crystal semiconductor substrate;
An adsorption layer containing a metal element adsorbed on the single crystal semiconductor substrate and having a single periodic structure aligned with an atomic arrangement on the surface of the single crystal semiconductor substrate;
A dielectric film formed on the adsorption layer;
An electrode formed on the dielectric film,
The standard generation enthalpies per unit oxygen of the oxide of the metal element constituting the adsorption layer, the oxide of the element of the single crystal semiconductor substrate, and the oxide of the metal element constituting the dielectric film are respectively ΔH _a , When ΔH _s and ΔH _d , the adsorption layer and the dielectric film are formed of a metal element that satisfies the relationship of ΔH _a ≧ ΔH _d and ΔH _s ≧ ΔH _d ,
If the unit cell of the unit cell of the cross-sectional structure of the semiconductor substrate is → a ₁ , → a ₂ , the unit cell of the periodic structure of the adsorption layer has a unit vector of 2 × → a ₁ , 1 × → a _2. A semiconductor device characterized by the above. The adsorption layer includes at least one element selected from Ti, Ba, Ra, and Zr, and the dielectric film includes ZrO ₂ , Zr ₂ Al ₂ O _7, and Ln ₂ Zr ₂ O ₇ (where Ln is Sc, 5. The semiconductor device according to claim 4, wherein the semiconductor device is any one of Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). 5. The semiconductor device according to claim 3, wherein the adsorption layer has a Ba / Si (100) 2 × 1 structure, and the dielectric film is HfAlON . Supplying a metal element to the surface of the single crystal semiconductor substrate;
Forming an adsorption layer having a single atomic arrangement that matches the atomic arrangement on the surface of the single crystal semiconductor substrate by heating the single crystal semiconductor substrate;
Forming a dielectric film on the adsorption layer;
Forming a gate electrode on the dielectric film;
With
The metal element is Sr;
The single atomic arrangement in the adsorption layer is a Sr / Si (100) 2 × 1 structure,
The step of forming the adsorption layer includes the step of desorbing excess Sr supplied from the semiconductor substrate by setting the heating temperature to 650 ° C. or higher and 850 ° C. or lower. Method. The step of forming the dielectric film is performed in an atmosphere having a substrate temperature of 200 ° C. to 700 ° C. and an oxygen partial pressure of 1 × 10 ⁻⁸ torr to 1 × 10 ⁻⁶ torr. 8. A method of manufacturing a semiconductor device according to 7.