JP3250996B2 - Silicon substrate having insulating film on surface and method and apparatus for manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon substrate having an insulating film on its surface and a method and an apparatus for manufacturing the same, and more particularly to a silicon substrate in which the thickness of an insulating film is controlled at an atomic level and a method and an apparatus for manufacturing the same. .

[0002]

2. Description of the Related Art In a variety of semiconductor devices, a semiconductor oxide film has a very large role as an insulating film. Therefore, much research has been conducted on the film quality and formation method. Regarding silicon oxide film manufacturing method, by SMSZE
"VLSI Technology, McGRAW-Hill", 98pp.-140pp. As a method of forming a semiconductor oxide film, a thermal oxidation step of exposing a semiconductor surface to an oxygen molecular gas at high temperature and atmospheric pressure is widely used. In this thermal process, the oxidation process of the semiconductor proceeds from the surface toward the inside, and as the oxide film grows, the interface of the oxide film moves into the semiconductor.

[0003] The oxidation mechanism in the oxidation process consists of the dissociation of oxygen molecules into atoms and the formation of chemical bonds between the dissociated oxygen atoms and semiconductor atoms. This reaction occurs mainly near the interface between the oxide film and the semiconductor. Therefore, in the initial oxidation when the interface is shallow, the reaction is rate-determined and the reaction proceeds rapidly. However, as the interface becomes deeper, oxygen needs to diffuse and move from the surface to the interface, so that the oxidation reaction is diffusion-controlled by oxygen and the growth of the oxide film is gradually slowed down.

In the initial oxidation process, which is reaction-limited,
Since the chemical adsorption of oxygen progresses rapidly, the progress of the reaction often differs depending on the location due to thermal fluctuation due to temperature or the like. In addition, due to the cleaning treatment of the semiconductor surface, unbonded bonds on the surface are terminated by other atoms and molecules, which hinders oxidation at a low temperature during a subsequent manufacturing process. For this reason, if the surface-terminated semiconductor surface is to be thermally oxidized as it is, an oxidation step of raising the temperature to 600 ° C. or higher from the beginning to accelerate the oxidation reaction by, for example, desorption of hydrogen is necessary. Suddenly 2
Oxidation progresses from the first layer onward, which causes an increase in unevenness of the oxide film thickness. Oxidation rate is reduced by subsequent growth of the oxide film, but oxidation proceeds while maintaining a non-uniform interface structure, and eventually an uneven interface is formed between the semiconductor and the oxide film. Had become.

The oxide film thus formed contains a relatively large density of states near the interface in the band gap. For example, when the oxide film is used as a gate insulating film of a MOS transistor, the variation in threshold voltage is large and the semiconductor device has a large variation in threshold voltage. Had led to a decrease in reliability.

[0006]

As described above, in the method of thermally oxidizing a semiconductor surface whose surface has been modified at a high temperature and an atmospheric pressure, it is difficult to form a uniform oxide film interface, and an uneven oxide film interface is formed. There was a problem that it would be formed.
In addition, in order to start oxidation from a clean surface, it is necessary to generate a clean surface from the modified surface, and therefore, it is necessary to perform high temperature treatment in an ultra-high vacuum or a non-oxidizing atmosphere in advance,
It also led to the complexity of the process.

On the other hand, with regard to formation of an oxide film on a clean silicon surface, Japanese Patent No. 2,880,993 discloses a thermal oxidation step capable of flattening an interface between silicon oxide and silicon at an atomic level. However, the problem of impurity contamination during the thermal oxidation step of clean silicon remains unsolved.

SUMMARY OF THE INVENTION The present invention has been made to solve the problem of reduced device reliability resulting from the conventional manufacturing process.
Focusing on the fact that unbonded bonds on the surface are inactivated, it has an atomic layer level oxide film that suppresses impurity contamination in the oxidation process and makes the interface between the oxide film and the semiconductor more flat and uniform. It is an object to provide a silicon substrate. Another object is to provide a silicon substrate having a silicon oxynitride film as an insulating film in place of the oxide film.

[0009]

In order to achieve the above-mentioned object, the present invention has been proposed in Japanese Patent Application No. 11-0113134.
Utilizes the phenomenon in which dimer bonds and back bonds around exposed unbonded bonds are oxidized. In the present invention, in addition to the above invention, the present invention has been made by focusing on a new discovery in which domino-like movement of atoms terminating an unbonded bond occurs. That is, when the dimer bond and the back bond around the unbonded bond are oxidized, the unbonded bond is terminated by the movement of atoms terminating the neighboring unbonded bond, and a new unbonded bond due to the movement of this atom is formed. And the discovery that oxidation is induced by this new unbonded bond. In other words, when oxidation that is triggered by an unbonded bond occurs, atoms terminating the unbonded bond in the vicinity of the unbonded bond move to the unbonded bond that has induced oxidation, and this is repeated, thereby causing a domino-like bond. Migration of atoms terminating unbonded bonds occurs.
Therefore, by dispersing the unbonded bonds almost uniformly on the substrate surface, not only can the entire surface be oxidized in a short time, but also the oxidation initiation site can be dispersed, so that the crystal distortion accompanying the oxidation can be reduced. Can be diversified. Thereby, particularly in the oxidation of the first layer, crystal expansion in the direction perpendicular to the crystal surface occurs uniformly, and the integrity of the interface between the oxide film and the silicon crystal can be ensured.

[0010] The first layer on the surface is completely oxidized in parallel with the surface by utilizing the movement of the terminated atoms, and thereafter the oxidation reaction is performed one layer at a time from the surface, and every time the oxidation reaction for each layer is completed. At the same time, by increasing the partial pressure ratio of the oxygen molecular gas to the gas that does not react with the semiconductor and / or the temperature of the semiconductor surface together with the growth of the oxide film, an oxide film having a required thickness and controlled at the atomic level is produced.

In this manner, since oxidation proceeds layer by layer from the initial stage, by increasing the partial pressure ratio of the oxygen molecular gas or the temperature of the semiconductor surface as the oxide film grows, it becomes flat and uniform at the atomic level. The oxide film grows while maintaining the interface structure.

According to the present invention, until the oxidation of the first surface layer is completed, the portions other than the unbonded bonds are terminated with atoms, so that intrusion of impurities during the oxidation reaction can be prevented. The number density of unbonded bonds before the oxidation reaction is approximately 10 ¹³ / cm ^{2 in} the case of the silicon (100) surface, but this value varies depending on the oxidation temperature and the oxygen partial pressure. Here, if an environment of nitriding is formed instead of oxidation, a silicon substrate having an oxynitride film as an insulating film can be formed as in the case of oxidation.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In forming an oxide film by the method of the present invention, it is desirable that a semiconductor surface which is flat at the atomic level is terminated with atoms or molecules. If the surface of the semiconductor subjected to the oxidation step is not flat, there is a high possibility that the interface of the formed oxide film is not flat.

The oxidation step of forming the first oxide film is performed at a product of the oxygen partial pressure and the oxidation time of from 10 ^-6 Torr · sec to 10 ^-2 Torr · sec from room temperature to 500 ° C. Is desirable. The higher the process temperature, the smaller this value can be.

The thickness of a gate insulating film used in a field effect transistor is decreasing year by year as the integration degree of a transistor is improved. For example, in a 1 gigabit random access memory device, it is required to reduce the film thickness to 3 nm or less. If the thickness of the SiO ₂ is thus thinner, Si / SiO ₂ interface disturbance at the atomic level, the crystal defects in the SiO _2, dislocations, problems such as dielectric breakdown voltage failure due to impurities reliable SiO ₂ insulating film Is an obstacle to the formation of When the film thickness of SiO ₂ is 2 nm or less, it becomes difficult to use it as an insulating film due to an increase in tunnel current. For this reason, a technique for directly depositing a high dielectric constant insulating material instead of SiO ₂ on a silicon surface is required.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view showing the structure of an oxide film forming apparatus used in an oxide film forming method according to one embodiment of the present invention. This oxide film forming apparatus accommodates a movable susceptor 2 that supports a plurality of semiconductor substrates 1 and includes a chamber 5 having an electron beam irradiation source 3 and a heating furnace 4. The chamber 5 is provided with an oxygen gas source 6, a nitrogen gas source 7 as an atmospheric gas, a gas inlet 8 for introducing oxygen gas and nitrogen gas, and a gas discharge valve 9 for controlling gas discharge. Valves 10 and 11 are attached to the oxygen gas source 6 and the nitrogen gas source 7, respectively, so that the gas partial pressure can be controlled. Around the heating furnace 4,
A heater 12 is provided and is controlled by a temperature control device.

FIG. 2 is a schematic diagram showing the atomic structure of an example of the silicon substrate before the initial oxidation employed in the present invention. (1
The silicon substrate 1 having the (00) plane as a main surface is treated with diluted hydrofluoric acid to form a structure in which unbonded bonds of the silicon substrate 1 are terminated with hydrogen as shown in FIG. Hereinafter, in the schematic diagram showing the atomic structure, a circle with a large hatching indicates a silicon atom, a slightly smaller white circle indicates an oxygen atom, and a smallest black circle indicates a hydrogen atom. In this case, adjacent silicon atoms on the outermost surface may be bonded by a dimer bond as shown on the left side of the drawing, or may have two independent hydrogen terminations. This hydrogen-terminated silicon substrate 1 is placed on the susceptor 2, and valves 9 and 11 are opened at room temperature.
By closing 0, the atmosphere in the chamber 4 is changed to only nitrogen gas, and then the valves 9 and 11 are closed. Therefore,
The silicon substrate 1 is irradiated with an electron beam from an electron beam irradiation source 3. The electron beam irradiation source 3 preferably scans the surface of the silicon substrate 1 with an electron beam having a predetermined electron density in order to obtain a predetermined electron density and uniformly irradiate the silicon substrate 1 with an electron beam. .

FIG. 3 shows an atomic structure in which a silicon substrate 1 in which unbonded bonds are terminated by hydrogen is irradiated with an electron beam to form unbonded bonds in which hydrogen is partially desorbed on the silicon surface. It is a schematic diagram.

In this state, the susceptor 2 on which the silicon substrate 1 is mounted is moved to the core, the substrate temperature is raised to 200 ° C., and the valves 9 and 10 are opened and closed to reduce the oxygen gas in the chamber 4 to 10 ^−. This temperature is maintained for one minute at an oxygen partial pressure of ⁶ Torr. By this operation, adsorption of oxygen molecules to unbonded bonds on the silicon surface occurs, and the oxygen molecules dissociate into oxygen atoms and are adsorbed by dimer bonds and back bonds, thereby oxidizing the silicon atoms. At this time, since the energy of hydrogen atoms is lower when bonded to oxidized silicon atoms, hydrogen atoms terminating the silicon surface of silicon atoms in the same dimer bond row move to this new unbonded bond . Thus, silicon atoms having new unbonded bonds are oxidized. In this way, when the atoms terminating the silicon surface are removed and become unbonded bonds,
The adsorption of the oxygen molecule to the unbonded bond triggers the domino movement of the terminal atom.

As a result, the entire silicon surface is oxidized. At this time, the silicon surface is exposed to the atmosphere of oxygen molecules. However, since the oxidation by the adsorption of oxygen molecules to the unbonded bond proceeds at the lowest energy, the oxidation to the second layer is not performed. It hardly occurs and only the first layer is oxidized.

Hereinafter, this oxidation phenomenon will be described more specifically with reference to FIGS.

FIGS. 4 and 5 are diagrams three-dimensionally expressing a part of the atomic structure shown in FIGS. 2 and 3. FIG.

In FIG. 4, S ₁ -S ₉ are silicon atoms, and H ₁ -H ₄ are hydrogen atoms terminating the outermost surface of the silicon substrate. The silicon atoms S ₁ -S ₅ correspond to the atoms forming the pentagon shown on the upper left side in FIG. The silicon atom S ₁ is bonded to the silicon atom S ₅ by a dimer bond, and is also bonded to the silicon atom S ₂ by a back bond. The silicon atom S ₅ is bonded with a silicon atom S ₄ and the back bond. Further, the silicon atom S ₁ is bonded to the silicon atom S ₆ on the back surface by a back bond, and the silicon atom S ₅ is bonded to the silicon atom S ₇ on the back surface by a back bond. The silicon atom S ₆ on the back surface is bonded to the silicon atom S ₈ by a back bond, and the silicon atom S ₇ is bonded to the silicon atom S ₉ by a back bond. Furthermore, silicon atom S ₈
Is bonded to the silicon atom S ₉ by a dimer bond. Further, silicon atoms on the outermost surface of the silicon substrate are terminated with hydrogen atoms H ₁ -H ₄ . In this way, the silicon atoms in the first layer, including those without reference numerals, extend in the [110] direction.

As shown in FIG. 5, for example, by electron beam irradiation, the silicon atom S ₁ dangling bonds D ₁ is removed hydrogen atom H ₁ terminating a is formed in an atmosphere of oxygen gas Bond D ₁ on the silicon substrate surface
Adsorbs oxygen molecules.

FIG. 6 is a schematic diagram showing an atomic structure showing this state, and oxygen molecules O ₁ -O ₂ are bonded to the unbonded bond D ₁ . Since this state is not stable, the oxygen molecule O ₁ −
O ₂ dissociates into oxygen atoms O ₁ and O ₂ and is adsorbed on, for example, a dimer bond or a back bond.

FIG. 7 shows that oxygen molecules dissociate into oxygen atoms O ₁ and O ₂ to bond silicon atoms S ₁ and silicon atoms S ₅ and dimer bonds and silicon atoms S ₁ and silicon atoms S _2. This shows the state of being adsorbed by the back bond. At this time, for the hydrogen atom because people bound to dangling bonds D ₁ lost oxygen molecule O ₁ -O ₂ is energetically stable, had terminated silicon atoms S ₈ that are joined by Daimabondo The hydrogen atom H ₃ moves and is terminated by the hydrogen atom H ₃ , and an unbonded bond D ₂ is newly generated in the silicon atom S ₈ .

FIG. 8 is a schematic diagram showing an atomic structure in a state where oxygen molecules O ₃ -O ₄ are adsorbed to a newly formed unbonded bond D ₂ , similarly to FIG. This state is the same as FIG. 6, and as described above, the oxygen molecules dissociate the oxygen atoms and enter the dimer bond or the back bond.

FIG. 9 shows that the oxygen molecules O ₃ -O ₄ adsorbed on the unbonded bond D ₂ in the atomic structure of FIG. 8 dissociate into oxygen atoms O ₃ and O ₄ , as in FIG. Dimer bond bonding silicon ₈ and silicon atom S ₉ and silicon atom S ₅
FIG. ₄ shows a state in which silicon is adsorbed by a back bond that bonds silicon atoms and silicon atoms S ₄ . At this time, as described with reference to FIG.
New is dangling bonds D ₃ is generated.

Here, in the description of FIG. 4 to FIG. 9, some of the back bonds appear to be left out of the oxidation, but this back bond is also oxidized in the course of the oxidation, which is a problem. Never. That is, the bonding of the oxygen molecule to the unbonded bond is not limited to one time, and the phenomenon in which the oxygen molecule is adsorbed and dissociated into oxygen atoms may be repeated several times. Looking at the case where hydrogen atoms are adsorbed to unbonded bonds and the case where oxygen molecules are bonded, when the temperature of the surface of the silicon substrate is high, hydrogen atoms are easily adsorbed to unbonded bonds, When the oxygen partial pressure is high, oxygen molecules are easily bonded. Therefore, if the control of both is devised, it is possible to eventually oxidize all dimer bonds and back bonds on the silicon substrate surface.

If there is a problem in the present embodiment, the domino-like movement of the atoms terminating the unbonded bonds occurs only in the dimer row, so that the atoms generated by the electron beam irradiation described with reference to FIG. If no unbonded bond is formed in one dimer row, the dimer row may not be subjected to oxidation treatment. However, this probability is extremely low, and oxidation is promoted by oxygen atoms dissociated by the surrounding unbonded bonds, so that this is not an essential problem.

FIG. 10 is a schematic diagram showing an atomic structure in which all the back bonds and dimer bonds of the first layer of the silicon substrate 1 are oxidized by the above-described first oxidation treatment. In the figure, 100 indicates the interface between the silicon layer and the oxide layer.

In this state, the valves 9, 10 and 1
1 is opened and closed to set the atmosphere in the chamber 4 to only nitrogen gas, and the substrate temperature is raised to 500 ° C. in 10 minutes. Thereafter, the valves 9 and 10 are opened and closed to raise the oxygen gas in the chamber 4 to an oxygen partial pressure of 10 ⁻⁵ Torr, and this temperature is maintained for 10 minutes. In this oxidation treatment, the first oxide layer described above is not affected,
Only oxidation of the second layer proceeds.

FIG. 11 is a schematic diagram showing an atomic structure in which all the bonds in the second layer of the silicon substrate 1 are oxidized by the above-described second oxidation treatment. In the figure, reference numeral 200 denotes an interface between the silicon layer and the oxide layer.

In this state, the valves 9, 10 and 1
1 is opened and closed to change the atmosphere in the chamber 4 to only nitrogen gas, and the substrate temperature is raised to 700 ° C. in 10 minutes. Thereafter, the valves 9 and 10 are opened and closed to raise the oxygen gas in the chamber 4 to an oxygen partial pressure of 10 ⁻³ Torr, and this temperature is maintained for 10 minutes. Even in this oxidation treatment, the first and second oxide layers described above are not affected, and only the oxidation of the third layer proceeds.

FIG. 12 is a schematic diagram showing an atomic structure in which all the bonds in the third layer of the silicon substrate 1 are oxidized by the above-described third oxidation treatment. In the figure, reference numeral 300 denotes an interface between the silicon layer and the oxide layer.

After that, when the oxygen partial pressure is raised to the same level as that of the atmosphere, the substrate temperature is raised to 850 ° C., and the substrate is exposed for 20 minutes, the oxidation reaction becomes diffusion-controlled, and the oxidation proceeds while maintaining a uniform interface structure. Then, a silicon oxide film having a thickness of 30 ° having a flat structure at the atomic level is formed.

In this embodiment, the hydrogen on the substrate surface is partially desorbed by the electron beam before the oxidation step is started. However, the desorption of hydrogen can be performed by a heat step or the like. All possibilities are conceivable.

In place of nitrogen gas, any kind of gas, for example, an inert gas such as argon can be used as long as it does not react with the semiconductor. Further, as a semiconductor, it can be applied to formation of an oxide film of any semiconductor that causes an oxidation reaction other than a silicon substrate.

The oxide film forming method described above can be applied to the formation of a gate insulating film of a MOSFET as shown in FIG. That is, as shown in FIG. 13, a field oxide film 14 is formed on a silicon substrate 13, a gate oxide film 15 and a gate electrode 16 are formed on the surface of an element region separated by the field oxide film 14, and ion implantation is performed. By forming the source region 17a and the drain region 17b, a MOSFET is obtained. In this case, the film thickness 3
The gate oxide film 15 of 0 Å can be formed by the oxide film forming method of the present invention.

The gate oxide film 1 thus formed
In No. 5, the interface is extremely uniform, and the MOSFET obtained as a result has a small variation in threshold voltage and exhibits stable characteristics.

In this embodiment, the formation of a silicon oxide film has been described. However, the principle of the present invention can be applied to the uniform formation of a silicon oxynitride film as an insulating film useful for a semiconductor device. . That is, the same treatment as the above-described oxidation treatment may be performed in an atmosphere of nitrogen oxide gas (NO) or a mixed gas of oxygen gas and nitrogen oxide gas (O ₂ + NO) instead of oxygen gas.

According to the present invention, an atomic layer oxide film useful as a deposition substrate for an insulating metal oxide thin film can be formed. When a metal oxide such as Ta ₂ O ₅ or BaTiO _{3 is} formed on a silicon substrate, conventionally, a silicon oxide film has been used as a buffer layer in order to prevent a circuit from being short-circuited by formation of a metal silicide. According to the present invention, the atomic layer oxide film is formed as an insulating silicon oxide film, and since the outermost surface is covered with hydrogen atoms or the like, it is possible to suppress the reaction between metal atoms and silicon atoms, This has the effect of preventing the formation of metal silicide.

[0044]

According to the present invention, only the first layer is oxidized from the unbonded bond to facilitate the subsequent oxidation. In the second and lower layers, the oxygen gas in the nitrogen gas is used by the oxygen gas as the oxide film grows. By increasing the partial pressure and the substrate temperature, it becomes possible to form an oxide film for each layer, a flat interface at the atomic level is formed, and the density of states in the band gap near the interface is greatly reduced. When applied as a gate oxide film of a MOS transistor, it is possible to form an element that performs uniform and stable operation with little variation in threshold voltage.

In the present invention, since only the first layer is oxidized by utilizing the diffusion of hydrogen, there is an advantage that the oxidation of each layer can be performed at a relatively low temperature even on the hydrogen-terminated semiconductor surface.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a structure of an oxide film forming apparatus used in an oxide film forming method according to an embodiment of the present invention.

FIG. 2 is a schematic view showing an atomic structure of an example of a silicon substrate before initial oxidation employed in the present invention.

FIG. 3 is a schematic view showing an atomic structure in which an unbonded bond in which hydrogen is partially eliminated is generated on a silicon surface by irradiating an electron beam to a silicon substrate 1 in which unbonded bonds are terminated by hydrogen.

FIG. 4 is a diagram three-dimensionally expressing a part of the atomic structure corresponding to FIG. 2;

FIG. 5 is a diagram three-dimensionally expressing a part of the atomic structure corresponding to FIG. 3;

FIG. 6 is a schematic diagram showing an atomic structure in a state where oxygen molecules are adsorbed to an unbonded bond having the atomic structure in FIG. 5;

FIG. 7 shows that oxygen molecules adsorbed on the unbonded bond having the atomic structure shown in FIG. 6 dissociate into oxygen atoms and are adsorbed on one of the dimer bond and the back bond, and the terminating atom moves to form a new unbonded bond. FIG. 4 is a schematic view showing an atomic structure in a generated state.

FIG. 8 is a schematic view showing an atomic structure in a state where oxygen molecules are adsorbed on a newly generated unbonded bond of FIG. 7;

FIG. 9 shows that an oxygen molecule adsorbed on an unbonded bond having the atomic structure of FIG. 8 dissociates into an oxygen atom and is adsorbed on one of a dimer bond and a back bond, and a terminating atom moves to form a new unbonded bond. FIG. 4 is a schematic view showing an atomic structure in a generated state.

FIG. 10 is a schematic diagram showing an atomic structure in which all of a back bond and a dimer bond of a first layer of a silicon substrate 1 are oxidized by a first oxidation treatment.

FIG. 11 is a schematic view showing an atomic structure in which all of a back bond and a dimer bond of a second layer of the silicon substrate 1 are oxidized by a second oxidation treatment.

FIG. 12 is a schematic view showing an atomic structure in which all of a back bond and a dimer bond of a third layer of the silicon substrate 1 are oxidized by a third oxidation treatment.

FIG. 13 is a sectional view showing a MOSFET having a gate oxide film formed according to an embodiment of the present invention.

[Explanation of symbols]

1: semiconductor substrate, 2: susceptor, 3: electron beam irradiation source, 4: heating furnace, 5: chamber, 6: oxygen gas source,
7: nitrogen gas source, 8: gas inlet, 9: gas outlet, 1
0, 11: valve, 12: heater, 13: silicon substrate, 14: field oxide film, 15: gate oxide film, 1
6: gate electrode, 17a: source region, 17b: drain region, S: silicon atom, H: hydrogen atom.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomihiro Hashizume 2520 Akanuma-cho, Hatoyama-cho, Hiki-gun, Saitama Prefecture Inside Hitachi, Ltd. Basic Research Laboratory Co., Ltd. Within the Basic Research Laboratories (72) Inventor Takeshi Uda 2520 Akanuma, Hatoyama-cho, Hiki-gun, Saitama Prefecture Within the Basic Research Laboratories, Hitachi, Ltd. Inside the Center (72) Inventor Toshihiro Uchiyama 1006 Odakadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-11-54503 (JP, A) JP-A-11-176828 (JP, A) JP-A-11-189497 (JP, A) JP-A-11-168097 (JP, A) JP-A-9-64030 (JP, A) JP-A-63 −7372 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/312 H01L 21/314 H01L 21/316 H01L 21/318 H01L 21/31 H01L 21/02

Claims (8)

(57) [Claims] 1. A silicon substrate having a 2 × 1 reconstructed surface or 1 × 1 reconstructed surface of a silicon (100) surface in which unbonded bonds on the surface are terminated by hydrogen atoms or deuterium atoms. An insulating film formed by removing hydrogen atoms or deuterium atoms terminating the substrate at a number density of about 10 ¹³ / cm ² on the entire surface of the substrate and then reacting with an oxygen atom-containing molecular gas to cover the entire surface. A silicon substrate comprising: 2. A silicon substrate having a 2 × 1 reconstructed surface or a 1 × 1 reconstructed surface of a silicon (100) surface in which unbonded bonds are terminated by hydrogen atoms or deuterium atoms. After removing the hydrogen atoms or deuterium atoms terminating the substrate over the entire surface of the substrate at a number density of about 10 ¹³ / cm ² , the substrate is reacted with a molecular gas containing oxygen atoms. By adding an oxidizing step in an atmosphere having an oxygen gas at a predetermined oxygen partial pressure in a temperature range exceeding 500 ° C. where atoms are detached from the substrate surface, oxidation is performed up to the second or third layer from the surface over the entire surface of the substrate. A silicon substrate characterized in that: 3. A substrate having a 2 × 1 reconstructed surface or a 1 × 1 reconstructed surface of a silicon (100) surface in which unbonded bonds on the surface are terminated by hydrogen atoms or deuterium atoms, Removing hydrogen atoms or deuterium atoms terminating the substrate surface over the entire surface of the substrate at a number density of about 10 ¹³ / cm ² , removing the substrate surface from which the terminating hydrogen atoms or deuterium atoms have been removed. A method for manufacturing a silicon substrate having an insulating film over the entire surface, comprising a step of oxidizing in an atmosphere having an oxygen gas at a predetermined oxygen partial pressure in a temperature range from room temperature to 500 ° C. or lower. 4. The method according to claim 1, further comprising, after the oxidizing step, oxidizing in an atmosphere having an oxygen gas at a predetermined oxygen partial pressure in a temperature range exceeding 500 ° C. at which the hydrogen atoms or deuterium atoms separate from the substrate surface. The method for manufacturing a silicon substrate according to claim 3. 5. The method according to claim 3, wherein the oxidation has a product of the oxygen partial pressure of the oxygen gas and the oxidation time in the range of 10 ⁻⁶ Torr · sec or more and 10 ⁻² Torr · sec or less, and has an insulating film of SiO _{2 on} the surface. 5. The method for manufacturing a silicon substrate according to 4. 6. An oxynitriding process using a nitrogen oxide gas or a mixed gas of the nitrogen gas and the oxygen gas instead of the oxidation using the oxygen gas, and having a silicon oxynitride film as an insulating film on the surface. A method for manufacturing a silicon substrate as described above. 7. A first means for holding and moving a silicon substrate whose surface is terminated by hydrogen atoms or deuterium atoms, and an atmosphere having a predetermined gas partial pressure and temperature around the first means. And hydrogen atoms or deuterium atoms terminating the silicon atoms S ₁ on the surface of the silicon substrate held by the first means over the entire surface of the substrate.
^An apparatus for manufacturing a silicon substrate, comprising: means for irradiating an electron beam to form an unbonded bond by removing at a number density of about ¹³ / cm ² . 8. A method for controlling an atmosphere having a gas partial pressure and a temperature, wherein the terminating hydrogen or deuterium atoms are removed from the entire surface of the substrate at a number density of about 10 ¹³ / cm ^2. In a temperature range from room temperature to 500 ° C.,
A step of oxidizing in an atmosphere having an oxygen gas having a predetermined oxygen partial pressure; and, after the oxidizing step, in a temperature range exceeding 500 ° C. at which the hydrogen atoms or deuterium atoms separate from the substrate surface, 8. The apparatus for manufacturing a silicon substrate according to claim 7, comprising two steps of oxidizing in an atmosphere containing oxygen gas.