JP2005515633A - Silicon wafer with ideal oxygen precipitation having nitrogen / carbon stabilized oxygen precipitation nucleation center and method for producing the same - Google Patents

Abstract

  A silicon wafer having a controlled oxygen precipitation behavior such that an oxygen precipitate in the bulk of the wafer is finally formed sufficient for intrinsic gettering and a denuded zone extending inwardly from the front surface. In particular, prior to the formation of oxygen precipitates, the wafer bulk portion has oxygen precipitation nucleation centers stabilized by dopants. The dopant is selected from the group consisting of nitrogen and carbon. The concentration of the dopant is sufficient to allow the oxygen precipitation nucleation center to withstand a heat treatment such as an epitaxial deposition process while maintaining the ability to dissolve any grown-in nucleation center.

Description

Detailed Description of the Invention

The present invention generally relates to the preparation of semiconductor material substrates, particularly silicon wafers, used in the manufacture of electronic components. In particular, the present invention enables silicon to form an ideal non-uniform depth distribution of oxygen precipitates on the wafer during the thermal processing cycle of essentially any electronic device manufacturing process. The present invention relates to a wafer processing method.

  Single crystal silicon, which is the starting material for most methods for the manufacture of semiconductor electronic components, is generally the so-called Czochralski method, in which a seed single crystal is dipped in molten silicon and then slowly pulled up to grow. process). Since molten silicon is contained in a quartz crucible, it is contaminated by various impurities, mainly oxygen. At the temperature of the silicon molten mass, until the oxygen concentration reaches a concentration determined by the actual segregation coefficient of oxygen in the solidified silicon and by the solubility of oxygen in the silicon at the temperature of the molten mass, Oxygen enters the crystal lattice. Its concentration is higher than the solubility of oxygen in solid silicon at temperatures typical for methods of manufacturing electronic devices. As crystals grow from the molten mass and are cooled, and therefore the oxygen solubility therein rapidly decreases, oxygen is present at a supersaturated concentration in the resulting slice or wafer.

  Thermal processing cycles commonly used in the manufacture of electronic devices cause oxygen precipitation on silicon wafers that are supersaturated with oxygen. Depending on the location of these oxygen deposits on the wafer, the deposits can be detrimental or beneficial. Oxygen precipitates located in the active device region of the wafer can impair device operation. However, oxygen precipitates located in the bulk of the wafer can trap unwanted metal impurities that can come into contact with the wafer. The use of oxygen precipitates located in the bulk portion of the wafer that captures the metal is commonly referred to as internal or intrinsic gettering (IG).

Historically, electronic device manufacturing methods have regions or sites free of oxygen precipitates (commonly referred to as “denuded zones” or “no-deposition zones”) near the surface of the wafer. However, the remainder of the wafer, the wafer bulk, had a series of steps designed to produce silicon with a sufficient number of oxygen precipitates for the IG. The denuded zone may be, for example, a high temperature-low temperature-high temperature thermal sequence, for example (a) an oxygen out-diffusion heat treatment at high temperature (> 1100 ° C.) for at least 4 hours in an inert atmosphere, ( b) Oxygen precipitate nucleation at low temperature (600 to 750 ° C.) and (c) Oxygen precipitate (SiO ₂ ) growth at high temperature (1000 to 1150 ° C.). See, for example, F. Shimura, “Semiconductor Silicon Crystal Technology”, Academic Press, Inc., San Diego California (1989), pages 361-367 and references cited therein.

  More recently, however, advanced electronic device manufacturing methods, such as DRAM manufacturing methods, have begun to address the use of high temperature process steps. Some of these processes maintain sufficient high temperature process steps to form a sufficient bulk precipitate density and denuded zone, but the product is a commercially viable product. To achieve this, the tolerance for the material is too strict. Other current highly advanced electronic device manufacturing methods do not have any out-diffusion steps. Therefore, due to problems associated with oxygen precipitates in the active device region, these electronic device manufacturers need to use silicon wafers that cannot form oxygen precipitates in any region of the wafer under their process conditions. There is. As a result, all IG potential is lost.

SUMMARY OF THE INVENTION Accordingly, among the objectives of the present invention, there is essentially a single that can form an ideal non-uniform depth of oxygen precipitate distribution during the thermal processing cycle of any electronic device manufacturing method. Providing a crystalline silicon wafer; Providing a wafer capable of optimally and reproducibly forming a denuded zone with sufficient density and depth of oxygen precipitates in the wafer bulk; Providing a wafer whose formation and formation of the denuded zone do not depend on the difference in oxygen concentration in these regions of the wafer; the thickness of the resulting denuded zone is essential to the details of the integrated circuit (IC) manufacturing process sequence Providing an independent wafer; the formation of oxygen precipitates and the formation of a denuded zone in the wafer bulk Providing a wafer that is unaffected by the oxygen concentration and thermal history of the Czochralski method single crystal silicon ingot to be fabricated; providing a method in which the formation of the denuded zone does not depend on oxygen outdiffusion; and At a concentration sufficient to stabilize the oxygen precipitation nucleation center so that the oxygen precipitation nucleation center can withstand subsequent rapid thermal processing without inhibiting denuded zone formation, silicon and nitrogen and / or Another object is to provide a method of doping with carbon.

In summary, therefore, the present invention relates to two generally parallel major surfaces, one on the front surface of the wafer and the other on the back surface of the wafer, a central plane between the front and back surfaces, and The present invention relates to a single crystal silicon wafer having an outer peripheral edge portion connecting the front surface and the rear surface. Wafer comprises a dopant selected from the group consisting of nitrogen and carbon, the concentration of the dopant, when cooling at a rate R of the wafer from the first temperature T ₁ to a second temperature T _2, stabilized It is sufficient to promote the formation of oxygen precipitation nucleation centers. Stabilized oxygen precipitation nucleation centers cannot dissolve at temperatures below 1150 ° C, but can dissolve at temperatures in the range of about 1150 ° C to about 1300 ° C. The temperature T ₁ is in the range of about 1150 ° C. to about 1300 ° C. Temperature T ₂ is the temperature at which crystal lattice vacancies are not relatively move in the silicon. The rate R is at least about 5 ° C./second. Furthermore, the wafer is a surface layer having a region of the wafer between a portion of the distance D measured from the front surface toward the center plane and the front surface, and having a stabilized oxygen precipitation nucleation center. It has a surface layer that does not have. Similarly, the wafer has a bulk layer having a stabilized oxygen precipitation nucleation center in the second region of the wafer between the central plane of the wafer and the surface layer.

The present invention includes two main surfaces that are generally parallel, one on the front surface of the wafer and the other on the back surface of the wafer, a central plane between the front and back surfaces, and the front surface. The present invention relates to a single crystal silicon wafer having an outer peripheral edge portion communicating with a rear surface. The wafer includes a dopant selected from the group consisting of nitrogen and carbon. When nitrogen is the dopant, the concentration of nitrogen ranges from about 1 × 10 ¹² to about 5 × 10 ¹⁴ atoms / cm ³ . When carbon is the dopant, the concentration of carbon ranges from about 1 × 10 ¹⁶ to about 4 × 10 ¹⁷ atoms / cm ³ . The wafer is a surface layer having a region of the wafer between a portion at a distance D measured from the front surface toward the center plane and the front surface, and having a stabilized oxygen precipitation nucleation center. Has no surface layer. In addition, the wafer has a bulk layer having a second region between the central plane of the wafer and the surface layer, and having a stabilized oxygen precipitation nucleation center.

In yet another example embodiment, the present invention provides a silicon-on-insulator structure having a single crystal handle wafer, a single crystal silicon device layer, and an insulating layer between the handle wafer and the device layer. The single crystal silicon handle wafer has two main surfaces generally parallel, one on the front surface of the wafer and the other on the back surface of the wafer, a central plane between the front and back surfaces, and It has an outer periphery that connects the front surface and the rear surface. The handle wafer includes a dopant selected from the group consisting of nitrogen and carbon, and the concentration of the dopant is determined when the wafer is cooled from the _first temperature T ₁ to the second temperature T ₂ at a rate R. The concentration is sufficient to promote the formation of stabilized oxygen precipitation nucleation centers. Stabilized oxygen precipitation nucleation centers cannot dissolve at temperatures below 1150 ° C., but can dissolve at temperatures in the range of about 1150 ° C. to about 1300 ° C. The temperature T ₁ is a temperature in the range of about 1150 ° C. to about 1300 ° C. Temperature T ₂ is the temperature at which crystal lattice vacancies are not relatively moved in silicon. The rate R is at least about 5 ° C./second. Further, the handle wafer is a surface layer having a region of the wafer between a portion of the distance D measured from the front surface toward the center plane and the front surface, and a stabilized oxygen precipitation nucleation center It has a surface layer which does not have. Similarly, the handle wafer has a bulk layer having a second region between the central plane of the wafer and the surface layer and having a stabilized oxygen precipitation nucleation center.

The invention further relates to a method for producing a single crystal silicon wafer having a controlled oxygen precipitate behavior. This method is a wafer sliced from a single crystal silicon ingot grown by the Czochralski method, comprising a front surface, a rear surface, a central plane between the front surface and the rear surface, and from the front surface to the central plane. Select a wafer having a front surface layer having a region of the wafer between the portion of distance D and the front surface measured toward the front, and a bulk layer having a region of the wafer between the central plane and the front surface layer. Comprising that. Wafer includes a dopant selected from the group consisting of nitrogen and carbon, the concentration of the dopant, when cooling the wafer from the first temperature T ₁ at the second temperature T ₂ to the speed R, stable The concentration is sufficient to promote the formation of oxygenated nucleation centers. Stabilized oxygen precipitation nucleation centers cannot dissolve at temperatures below 1150 ° C., but can dissolve at temperatures in the range of about 1150 ° C. to about 1300 ° C. The temperature T ₁ is a temperature in the range of about 1150 ° C. to about 1300 ° C. Temperature T ₂ is the temperature at which crystal lattice vacancies are not relatively moved in silicon. The rate R is at least about 5 ° C./second. Furthermore, the method includes heating the wafer to a temperature of at least about 1150 ° C. to produce crystal lattice vacancies in the front surface layer and the bulk layer, and the heated wafer has a peak vacancy density in the bulk layer. The concentration of vacancies decreases as a whole from the position of peak density toward the front surface of the wafer, and the difference between the vacancy concentration of the front surface and the vacancy concentration of the bulk layer is stabilized by oxygen precipitation. Cooling at a rate that produces a vacancy concentration profile in the wafer such that nucleation centers do not form on the front surface and stabilized oxygen precipitation nucleation centers form in the bulk layer.

In yet another aspect, the present invention relates to a method for producing a single crystal silicon wafer having controlled oxygen precipitate behavior. This method is a wafer sliced from a single crystal silicon ingot grown by the Czochralski method, comprising a front surface, a rear surface, a central plane between the front surface and the rear surface, and from the front surface to the central plane. Select a wafer having a front surface layer having a region of the wafer between the portion of distance D and the front surface measured toward the front, and a bulk layer having a region of the wafer between the central plane and the front surface layer. Comprising that. The wafer has a dopant selected from the group consisting of nitrogen and carbon. When nitrogen is the dopant, the concentration of nitrogen ranges from about 1 × 10 ¹² to about 5 × 10 ¹⁴ atoms / cm ³ . When carbon is the dopant, the concentration of carbon ranges from about 1 × 10 ¹⁶ to about 4 × 10 ¹⁷ atoms / cm ³ . The method comprises subjecting the wafer to a heat treatment to produce crystal lattice vacancies in the front surface layer and the bulk layer. The cooling of the heat-treated wafer is performed by using the heated wafer, in which the vacancy peak density is present in the bulk layer, and the vacancy concentration decreases as a whole from the position of the peak density toward the front surface of the wafer. The difference between the vacancy concentration of the surface and the vacancy concentration of the bulk layer shows that the stabilized oxygen precipitation nucleation center is not generated on the front surface, but the stabilized oxygen precipitation nucleation center is generated on the bulk layer. The vacancy concentration profile is generated at such a speed as to generate in the wafer. Further, when the heat-treated wafer is cooled, a stabilized oxygen precipitation nucleation center is generated in the bulk layer, and the concentration of the stabilized oxygen precipitation nucleation center in the bulk layer mainly depends on the vacancy concentration. To do.
Other objects and features of the invention will be in part apparent and in part will be pointed out hereinafter.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In accordance with the present invention, during a method of manufacturing essentially any electronic device, a wafer bulk containing a sufficient density of oxygen for IG and a sufficiently deep denuded zone are provided. Wafers have been found that provide an ideal deposition that can be formed. This ideal deposition wafer can be prepared in a few minutes using tools commonly used in the semiconductor silicon manufacturing industry. This method creates a “template” in the silicon substrate wafer that determines or “prints” the manner in which oxygen will eventually precipitate. In the present invention, this template is stable so that it can survive after subsequent rapid thermal processing (eg, epitaxial deposition and / or oxygen implantation) without the need for intervening thermal stabilization annealing. It becomes.

A. Starting Material The starting material for the ideal deposition wafer of the present invention is a single crystal silicon wafer containing nitrogen and / or carbon as dopants. The concentration of the dopant depends on two desirable properties: (i) an ideal template (ie, a denuded zone without oxygen precipitates and an intrinsic gettering region in the wafer bulk with oxygen precipitates), which ultimately results in oxygen The ability to dissolve any oxygen precipitation nucleation centers in the starting wafer to precipitate; and (ii) the nucleation centers are subsequently subjected to rapid thermal treatment (rapid thermal treatment), eg, epitaxial Adapted to the ability to grow sufficiently large or stable oxygen precipitation nucleation centers during the process of the present invention so that it does not dissolve during deposition or disappear the introduced precipitate template Chosen to do. In order to achieve the benefits of stabilization while retaining the ability to create a denuded zone, the concentration of dopant in the silicon is typically about 1 × 10 ¹² atoms / cm ³ (about 0.00002 ppma) to The range is 1 × 10 ¹⁵ atoms / cm ³ (about 0.02 ppma). In another embodiment of the present invention, the concentration of nitrogen ranges from about 1 × 10 ¹² atoms / cm ³ (about 0.00002 ppma) to about 1 × 10 ¹³ atoms / cm ³ (about 0.0002 ppma). If the concentration of nitrogen is too low, for example about 1 × 10 ¹² atoms / cm ³ (about 0.00002 ppma) or less, the stabilizing effect is not achieved (ie disappears at a temperature of about 1150 ° C. or less). On the other hand, if the concentration of nitrogen is too high, for example greater than or equal to 1 × 10 ¹⁵ atoms / cm ³ (about 0.02 ppma), the oxygen precipitation nucleation center formed during crystal growth is the method of the present invention. It does not dissolve during the rapid thermal annealing process.

  In addition, if the silicon crystal contains too much nitrogen, the quality of the wafer is adversely affected, and oxidation induced stacking faults (OISF) that some epitaxial layers are deposited tend to form on the entire wafer. (See Japanese Patent Laid-Open No. 11-189493 (1999-189493)). In particular, the OISF on the surface of the silicon wafer is not covered by the deposition of an epitaxial silicon layer, unlike other vacancy-type defects. The OISF continues to grow through the epitaxial layer and can result in crystal-grown-in defects commonly referred to as epitaxial stacking faults. Epitaxial stacking faults have a maximum cross-sectional width ranging from about 0.1 μm, which is the current detection limit of laser-based automatic inspection devices, to about 10 μm or more.

In accordance with the present invention, the wafer may contain carbon instead of or with nitrogen to stabilize the oxygen precipitation nucleation centers. In one embodiment, the concentration of carbon in silicon ranges from about 1 × 10 ¹⁶ atoms / cm ³ (about 0.2 ppma) to 4 × 10 ¹⁷ atoms / cm ³ (about 8 ppma). In another embodiment of the present invention, the concentration of carbon ranges from about 1.5 × 10 ¹⁶ atoms / cm ³ (about 0.3 ppma) to about 3 × 10 ¹⁷ atoms / cm ³ (about 6 ppma).

Czochralski grown silicon generally has an interstitial oxygen concentration in the range of about 5 × 10 ¹⁷ to about 9 × 10 ¹⁷ atoms / cm ³ (ASTM standard F-121-83). Since the oxygen precipitate behavior of the wafer is decoupled from the oxygen concentration in the ideal deposition wafer, the starting wafer can be in any range that can be within or outside the range achieved by the Czochralski method. Having an oxygen concentration within.

  During the growth of a silicon single crystal ingot containing nitrogen and / or carbon below typical impurity levels, the silicon is cooled from its melting point (about 1410 ° C.) and passed through a temperature range of about 700 ° C. to about 350 ° C. As it cools, the vacancies and oxygen can interact to produce oxygen precipitation nucleation centers in the ingot. Without being bound by any particular theory, it is now believed that nitrogen / carbon dopant atoms promote the formation of oxygen precipitate nucleation centers by slowing the diffusion of vacancies in single crystal silicon. In particular, when the nitrogen and / or carbon concentration increases above the impurity level, the concentration of vacancies at a given temperature also increases, thereby increasing the temperature at which critical supersaturation of oxygen and vacancies occurs. As a result, the critical supersaturation temperature of silicon having nitrogen and / or carbon concentrations within the scope of the present invention shifts from about 800 ° C. to about 1050 ° C. At higher critical supersaturation temperatures, the vacancy concentration is higher and the oxygen atoms are more mobile, thereby increasing the interaction between the two species and producing larger and more stable oxygen precipitation nucleation centers. .

According to the present invention, the presence or absence of nucleation centers in the starting material can be dissolved by heat treating the silicon at a temperature in the range of about 1150 ° C. to about 1300 ° C. Not very important. Although the presence (or density) of oxygen precipitation nucleation centers cannot be directly measured using techniques available today, the presence of an oxygen precipitation heat treatment, eg, a wafer at a temperature of 800 ° C. 4 It can be detected by subjecting to a heat treatment for 16 hours, followed by annealing at a temperature of 1000 ° C. for 16 hours. The detection limit for oxygen precipitates is today about 5 × 10 ⁶ precipitates / cm ³ .

Wafers are sliced from ingots grown by conventional Czochralski crystal growth methods. During ingot growth, nitrogen and / or in the ingot may be obtained in several ways, such as by introducing gaseous nitrogen / carbon into the growth chamber and / or adding solid nitrogen / carbon to the polysilicon melt. Alternatively, carbon can be introduced. The amount of dopant added to the growing crystal can be more precisely controlled by the addition of solid dopant to the polysilicon melt (which is typically used per se). For example, the amount of nitrogen / carbon added to the crystal can, for example, be applied to a silicon carbide (SiC) of known thickness on a silicon wafer of known diameter introduced into a crucible with polysilicon prior to forming the silicon melt. ) Or silicon nitride (Si ₃ N ₄ ) layers can be readily determined (the densities of Si ₃ N ₄ and SiC are about 3.18 g / cm ³ and about 3 respectively. .21 g / cm ³ ).

  Standard Czochralski growth methods and standard silicon slicing, lapping, etching and polishing techniques are described in F. Shimura's “Semiconductor Silicon Crystal Technology”, Academic press, Inc., 1989 and Silicon Chemical Etching ( J. Grabmaier), Springer-Verlag, New York, 1982 (incorporated herein by reference). The starting material for the method of the present invention may be a polished silicon wafer or a silicon wafer that has been lapped and etched but not polished. In addition, the wafer may have vacancies or self-interstitial defects as the dominant intrinsic point defects. For example, a wafer has dominant vacancies from the central part to the peripheral part, dominant self-interstitial atoms from the central part to the peripheral part, or self-interstitial in the form of an axisymmetric ring. It may have a central core of vacancy dominant material surrounded by atomic dominant material.

Processing Method Referring to FIG. 1, a single crystal silicon wafer 1 that is the starting material of an ideal deposition wafer of the present invention includes a front surface 3, a rear surface 5, and a virtual central plane between the front surface and the rear surface. 7. In this specification, the terms “front” and “back” are used to distinguish between two main surfaces of a wafer that are generally planar; the front surface of a wafer refers to this term herein. When used, it is not necessarily the surface on which the electronic device is subsequently assembled, and the rear surface of the wafer is not necessarily the main surface of the wafer opposite to the surface on which the electronic device is assembled when the term is used herein. It is not the surface. In addition, silicon wafers typically have some total thickness variation (TTV), warp and bow, so that each point on the front surface and each of the back surface The midpoint between each point may not be included in exactly one plane, however, as a practical matter, the degree of TTV, warpage and curvature is generally very small, so in a close approximation, Such a midpoint can be expressed as being contained in a virtual midplane that is approximately the same distance between the front and back surfaces.

B. According to the present invention, the wafer is heated to a high temperature by subjecting the wafer to a heat treatment step, step S2 (optional step S1 will be described later). As a result, crystal lattice vacancies 13 are formed in the wafer 1, and the number density of the crystal lattice vacancies 13 is thereby increased. This heat treatment step rapidly heats the wafer to the target temperature and anneals at that temperature for a relatively short time (eg, the wafer can be heated from room temperature to 1200 ° C. in a few seconds). Preferably, it is carried out with a rapid thermal annealer. One such commercially available RTA furnace is the model 2800 furnace commercially available from STEAG AST Electronic GmbH (Dornstadt, Germany). Generally, the wafer is subjected to a temperature above 1150 ° C. but not higher than about 1300 ° C. Generally, the wafer is subjected to a temperature in the range of about 1200 ° C to 1275 ° C, more typically in the range of about 1225 ° C to 1250 ° C.

  Endogenous point defects (vacancies and silicon self-interstitials) can diffuse through single crystal silicon at a diffusion rate that depends on temperature. Thus, the concentration profile of intrinsic point defects is a function of the recombination velocity as a function of temperature and the diffusivity of intrinsic point defects. For example, intrinsic point defects can move relatively at temperatures near the temperature at which the wafer is annealed in the rapid thermal annealing process, but at temperatures as high as 700 ° C. at any commercially practical interval time. Cannot move. According to experimental evidence obtained so far, the effective diffusion rate of vacancies is considerably slower at temperatures below about 700 ° C. and possibly at temperatures of 800 ° C. or 900 ° C. or even 1000 ° C. At lower temperatures, it can be considered that the vacancies do not move at any commercially practical interval time.

  In addition to causing the formation of crystal lattice vacancies, the rapid thermal annealing process causes the dissolution of existing oxygen precipitation nucleation centers present in the silicon starting material. These nucleation centers can be formed, for example, during the growth of a single crystal silicon ingot that slices the wafer, or some other event in the previous thermal history of the wafer or the ingot in which the wafer was sliced ( event). Therefore, whether such nucleation centers are present in the starting material is not very important if these nucleation centers can be dissolved during the rapid thermal annealing step.

  During thermal processing, the wafer is exposed to an atmosphere containing one or more gases selected to form a vacancy concentration profile that is relatively uniform in one aspect and non-uniform in another aspect. Is done.

1. Embodiments of non-nitriding and non-oxidizing atmospheres In one embodiment, the wafer 1 is heat treated in a non-nitriding atmosphere and a non-oxidizing atmosphere (ie, an inert atmosphere). Is done. When using non-nitrogen-containing and non-oxygen-containing gases as the atmosphere or environment in the rapid thermal annealing and cooling processes, increasing the concentration of vacancies throughout the wafer, if not quickly, will reach the annealing temperature. Almost achieved. The profile of vacancy concentration (number density) obtained in the wafer during the heat treatment is relatively constant from the front surface of the wafer to the back surface of the wafer. The wafer is generally at this temperature for at least 1 second, typically at least several seconds (eg, at least 3 seconds), preferably tens of seconds (eg, 20 seconds, 30 seconds, 40 seconds, or 50 seconds), And depending on the desired properties of the wafer, it is held at a time that can range up to about 60 seconds (which is nearly the limit for commercially available rapid thermal annealers). Holding the wafer for more time at the temperature formed during annealing would not lead to an increase in vacancy concentration based on experimental evidence available today. Suitable gases include argon, helium, neon, carbon dioxide and other such inert element and compound gases, or mixtures of these gases.

  Based on the experimental evidence obtained to date, the non-nitriding / non-oxidizing atmosphere preferably has oxygen, water vapor and other oxidizing gases at a relatively low partial pressure; Is either in the absence of any oxidizing gas or in order to inject a sufficient amount of silicon self-interstitial atoms such that the partial pressure of such gas suppresses the growth (or increase) of the vacancy concentration. Is included in an insufficient degree. The lower limit concentration of the oxidizing gas has not been determined exactly, but is about 0.01 atmospheres (atm), ie, about 10,000 parts per million atomic (ppma) (parts per million atomic) oxygen partial pressure. It has been shown that there is no increase in pore concentration and no effect. Accordingly, the atmosphere preferably has a partial pressure of oxygen and other oxidizing gases of 0.01 atm (10,000 ppma) or less; the partial pressure of these gases in the atmosphere is about 0.005 atm (5,000 ppma). Is more preferably about 0.002 atm (2,000 ppma) or less, and most preferably about 0.001 atm (1,000 ppma) or less.

2. Surface Oxide Layer / Nitriding Atmosphere Aspect In another aspect of the method of the invention, prior to step S2, in step S1, the wafer 1 is heat treated in an oxygen-containing atmosphere to surround the wafer 1 The material layer 9 is grown. In general, the oxide layer will have a greater thickness than the native oxide layer (about 15 cm) that forms on the silicon surface. In another aspect, the thickness of the oxide layer is generally at least about 20 mm. In some embodiments, the wafer will have a thickness of at least about 25 or 30 inches. Experimental evidence obtained to date has shown that oxide layers with a thickness of more than about 30 mm do not interfere with the desired effect, but provide no or little further advantage.

After forming the oxide layer, it is typically a nitriding atmosphere, ie, nitrogen gas (N ₂ ) or a nitrogen-containing compound gas, in the presence of a gas, such as ammonia, that can nitride the exposed silicon surface. A rapid thermal annealing process is performed. Alternatively or additionally, the atmosphere can include non-oxidizing and non-nitriding gases such as argon. When the annealing temperature is reached, an increase in vacancy concentration throughout the wafer is achieved, if not rapidly, and the vacancy concentration profile in the wafer is relatively uniform.

3. Embodiment of native oxide layer / nitriding atmosphere In the third embodiment, the starting wafer has a slight native oxide layer. When such a wafer is annealed in a nitriding atmosphere, the effect is different from the effect observed for the second embodiment. In particular, when annealing a wafer having an improved oxide layer (enhanced oxide layer) in a nitrogen atmosphere, the annealing temperature is reached, if not rapidly, if the vacancy concentration is substantially reduced. A uniform increase is achieved over almost the entire wafer; furthermore, at a given annealing temperature, the vacancy concentration is observed not to increase significantly as a function of annealing time. If the wafer has only a natural oxide layer and the front and back surfaces of the wafer are annealed in nitrogen, the resulting wafer is generally “U-shaped” voids in the cross section of the wafer. Will have a concentration (number density) profile; that is, the maximum concentration of vacancies is present at or within a few micrometers of the front and back surfaces and is relatively low compared to it. A certain concentration will be present throughout the bulk of the wafer. Its minimum concentration in the wafer bulk is initially approximately equal to that obtained in a wafer having an enhanced oxide layer. Furthermore, increasing the annealing time results in an increase in vacancy concentration in a wafer having only a natural oxide layer.

  Thus, referring again to FIG. 1, when a segment having only a native oxide layer is annealed according to the method of the present invention in a nitriding atmosphere, the peak concentration or maximum concentration of vacancies obtained is initially in regions 15 and 15 While the bulk portion 17 of the silicon segment will have a relatively lower concentration of vacancies and nucleation centers. Generally, these peak concentration regions are in the range of a few microns (eg, about 5-10 microns) from the silicon segment surface, or in the range of tens of microns (eg, about 20 or 30 microns) from the silicon segment surface. And will be in the range of about 40 microns to about 60 microns.

4). Oxygen-containing atmosphere If the atmosphere or environment in the rapid thermal annealing process and the cooling process contains oxygen, or in particular such an atmosphere or environment in combination with nitrogen-containing gas, inert gas or both, oxygen gas ( When containing O ₂ ) or an oxygen-containing gas (eg, pyrogenic steam), the vacancy concentration profile in the region near the surface is affected. Experimental evidence obtained to date indicates that the vacancy concentration profile in the region near the surface has an inverse relationship with the oxygen concentration in the atmosphere. Without being bound by any particular theory, annealing in oxygen at a sufficient concentration will oxidize the silicon surface, resulting in flux inside the silicon self-interstitals. It is generally believed that the resulting effect is obtained. The flux of silicon self-interstitials is controlled by the rate of oxidation, which can be controlled by the partial pressure of oxygen in the atmosphere. This inward flux of silicon self-interstitial atoms increases the rate of inward movement as a function of increasing oxygen partial pressure, starting at the surface and then moving inward to cause recombination. Thus, the pore concentration profile is gradually changed. When oxygen is used in combination with a nitrogen-containing gas in the atmosphere during heat treatment (S1 and / or S2), there is a maximum vacancy concentration or peak vacancy concentration in the wafer bulk portion between the central plane and the surface layer. , “M-shaped” pore profiles can be obtained in which the concentration gradually decreases in each direction. The presence of oxygen in the atmosphere can result in the formation of any arbitrarily low vacancy concentration regions.

  Furthermore, the difference between the behavior of a wafer having only a native oxide layer and the behavior of a wafer having an enhanced oxide layer should be eliminated by including molecular oxygen or other oxidizing gas in the atmosphere. Experimental evidence further suggests that this is possible. In other words, when a wafer having only a native oxide layer is annealed in a nitrogen atmosphere containing low partial pressure oxygen, the wafer behaves in the same manner as a wafer having an enhanced oxide layer (i.e., within a heat-treated wafer). A relatively uniform density profile is formed. Without being bound by any particular theory, a surface oxide layer that is thicker than the native oxide layer is observed to act as a shield to prevent silicon nitridation. Thus, this oxide layer can be formed on the starting wafer by existing or growing an enhanced oxide layer in situ during the annealing process. If desired, the atmosphere during the rapid thermal annealing step preferably comprises a partial pressure of at least about 0.0001 atm (100 ppma), more preferably at least about 0.0002 atm (200 ppma). However, for the reasons described above, the partial pressure of oxygen preferably does not exceed 0.01 atm (10000 ppma), preferably 0.005 atm (5000 ppma) or less, and more preferably 0.002 atm (2000 ppma) or less. , And most preferably 0.001 atm (1000 ppma) or less.

Thus, in the fourth embodiment, the atmosphere during the rapid thermal annealing process generally has an oxygen partial pressure sufficient to obtain a denuded zone depth of about 30 microns or less. In general, the denuded zone depth ranges from about 5 microns to about 30 microns, may range from about 10 microns to about 25 microns, or ranges from about 15 microns to about 20 microns. It may be. In particular, the heat treatment is performed using a nitrogen-containing gas (for example, N ₂ ), a non-oxygen-containing / non-nitrogen-containing gas (for example, argon or helium), or a mixture thereof, and an oxygen-containing gas (for example, O ₂ or high-temperature steam). Can be performed in an atmosphere containing The atmosphere is an oxygen partial pressure (eg, at least about 1 ppma, 5 ppma, 10 ppma or more) sufficient to produce a flux inside the self-interstitial atoms, and about 500 ppma or less, preferably about 400 ppma or less. 300 ppma or less, 200 ppma or less, 150 ppma or less or partial pressure which may be 100 ppma or less, and in some embodiments, oxygen content which may be about 50 ppma or less, about 40 ppma or less, about 30 ppma or less, about 20 ppma or less or about 10 ppma or less Have pressure. When a mixture of a nitrogen-containing gas and a non-nitrogen-containing / non-oxygen-containing gas is used together with an oxidizing gas, the ratio of each of the two gases (for example, the ratio of the nitrogen-containing gas to the inert gas) is about 1 : 10 to about 10: 1, about 1: 5 to about 5: 1, about 1: 4 to about 4: 1, about 1: 3 to about 3: 1, or about 1: 2 to about 2: 1. In some embodiments, the ratio of nitrogen-containing gas to inert gas is preferably 1: 5, 1: 4, 1: 3, 1: 2, 1: 1. In other words, when such a gas mixture is used as an atmosphere for the annealing and cooling steps, the concentration of the nitrogen-containing gas therein ranges from about 1% to about 100% or less, from about 10% to about 90%. In the range of about 20% to about 80%, or in the range of about 40% to about 60%.

5. Simultaneous exposure to different atmospheres In another aspect of the invention, the front and back surfaces of a wafer are exposed to (or exposed to) different atmospheres that may each contain one or more nitriding or non-nitriding gases. Can do. For example, the back surface of the wafer can be exposed to a nitriding atmosphere while the front surface of the wafer is exposed to a non-nitriding atmosphere. Wafers exposed to heat treatments having different atmospheres can have an asymmetric concentration profile depending on the conditions of each surface and the atmosphere to which it is exposed. For example, when the front surface has no layers other than the native oxide layer (thus having only the native oxide layer), the rear surface has an enhanced oxide layer, and the wafer is heat-treated in a nitriding atmosphere. The vacancy concentration in the front part of the wafer is approximated by a “U-shaped” profile, while the rear part of the wafer can be more homogeneous in nature. Alternatively, the plurality of wafers can be annealed simultaneously as an arrangement in which multiple (eg, 2 or 3 or more) wafers are stacked face-to-face. When annealed in this way, the faces that face each other are mechanically shielded from the atmosphere during annealing. Alternatively, depending on the atmosphere used during the rapid thermal annealing process and the desired oxygen precipitate profile of the wafer, an oxide layer is formed on only one surface of the wafer (eg, the front surface 3). You can also

C. Rapid Cooling Step of Doped and Heat Treated Silicon Wafer When step S2 is completed, in step S3, the crystal lattice vacancies pass through a temperature range in which the crystal lattice vacancies can move relatively in the single crystal silicon. There the temperature T ₂ which can not be relatively moved, to rapidly cool the wafer. When the temperature of the wafer is lowered through this temperature range, the vacancies diffuse and disappear on the surface of the wafer and / or the native oxide layer on the wafer surface, thus maintaining the wafer at a temperature within this range. The degree of change in the pore concentration profile is guided by the degree of change according to the time length to be performed. If the wafer is kept at this range of temperature for an infinite time, the vacancy concentration profile will again be similar to the initial profile of step S2 (eg, to a non-uniform “U-shaped” or asymmetric profile). However, the equilibrium concentration will be lower than the concentration immediately after the heat treatment step is completed. However, by rapidly cooling the wafer, the distribution of crystal lattice vacancies in the region near the surface is significantly reduced, resulting in a modified vacancy concentration profile. For example, by rapidly cooling a wafer that initially has a uniform profile, the maximum vacancy concentration is at or near the central plane 7 and the front surface 3 of the wafer and A non-uniform profile is obtained in which the vacancy concentration decreases in the direction of the rear surface 5. When the vacancy concentration profile is “U-shaped” before cooling, the final concentration profile after rapid cooling of the wafer is “M-shaped”. That is, the vacancy concentration profile has a local minimum concentration near the central plane, similar to the “U-shaped” profile prior to rapid cooling, and one of the central planes is suppressed by suppressing vacancies in the surface region. And the front surface, the other will have two local maximum concentrations between the midplane and the back surface. Finally, if the vacancy concentration profile before cooling is asymmetric, the final concentration has a local maximum concentration between the central plane and one surface, similar to the “M-shaped” profile. Similar to the profile formed after cooling one with a uniform concentration profile, it will generally decrease from the central plane to another surface.

  In general, the average cooling rate R is at least about 5 ° C./second, preferably at least about 20 ° C./second, in this temperature range. Depending on the depth of the desired denuded zone, the average cooling rate is preferably at least about 50 ° C./second, more preferably at least about 100 ° C./second, and for some applications today, A cooling rate of 100 ° C. to about 200 ° C./second is preferred. Once the wafer is cooled to a temperature outside the temperature range within which crystal lattice vacancies can move relatively in single crystal silicon, the cooling rate does not significantly affect the deposition characteristics of the wafer and is therefore narrow. The range will not be observed as important. As noted above, experimental evidence available today indicates that the effective diffusion rate of vacancies is typically significantly slower at temperatures below about 700 ° C., and at commercially lower temperatures at lower temperatures. It is thought that vacancies cannot move inside. It would be advantageous if the cooling step could be carried out in the same atmosphere as the heating step.

  During step S3, the vacancies in the wafer and the self-interstitial oxygen atoms interact to produce oxygen precipitation nucleation centers. The concentration of the oxygen precipitation nucleation center depends mainly on the vacancy concentration, and similarly, the profile of the oxygen precipitation nucleation center corresponds to the concentration profile of the vacancies. In particular, oxygen precipitation nucleation centers are generated in the high vacancy region (wafer bulk portion), and no oxygen precipitation nucleation centers are generated in the low vacancy region (portion near the wafer surface). In this way, by dividing the wafer into regions having various vacancy concentrations, a template for oxygen precipitation nucleation center is formed. Furthermore, the distribution of oxygen precipitation nucleation centers in the wafer bulk portion corresponds to the distribution of vacancies. That is, the distribution is non-uniform, for example, having an “M-shaped” or asymmetric distribution that has a maximum density at or near the central plane and decreases in the direction of the front and back surfaces. Can have a profile characterized by

  According to the present invention, the oxygen precipitation nucleation center formed in the wafer bulk portion is “stabilized” after the rapid thermal annealing step is completed. That is, no subsequent long-term (eg, time unit) heat treatment is required to grow nucleation centers to dimensions that can withstand rapid thermal treatment (rapid thermal processing), such as epitaxial deposition. As mentioned above, nitrogen and / or carbon dopant atoms retard the diffusion of vacancies in the silicon and thereby stabilize the oxygen precipitation nucleation centers (thus, they can dissolve at temperatures below about 1150 ° C. Today, it is believed that the temperature at which critical supersaturation of the vacancies that ultimately form) increases will occur.

  After step S3, the wafer has an area of the wafer between the front surface and a portion of distance D as measured from the front surface toward the central plane and has no oxygen precipitation nucleation center. A surface layer and a second layer of the wafer between the central plane and the first region, the bulk layer having a stabilized oxygen precipitation nucleation center. Depending on the dopant concentration in the wafer, the stabilized oxygen precipitation nucleation centers can be dissolved at a temperature in the range of about 1150 ° C. to about 1300 ° C. Thus, the stabilized oxygen precipitation nucleation center can withstand subsequent heat treatment, eg, epitaxial deposition, without interfering with the dissolution of the grown-in oxygen precipitation nucleation center during step S2. it can.

D. Oxygen Precipitate Growth In step S4, the wafer is subjected to an oxygen precipitate growth heat treatment to grow stabilized oxygen precipitate nucleation centers into oxygen precipitates. For example, annealing of the wafer can be performed at a temperature of 800 to 1000 ° C. for 16 hours. Alternatively and preferably, as a first step in the electronic device manufacturing process, the wafer can be placed in a furnace at 800-1000 ° C. When the temperature is raised to 800 ° C. or higher, oxygen precipitation nucleation clusters grow into precipitates by consuming vacancies and self-interstitial oxygen, while oxygen precipitation nucleation occurs in the region near the surface. No center is created and nothing happens.

  As shown in FIG. 1, the depth distribution of the oxygen precipitates obtained in the wafer is such that the oxygen precipitate-free materials 15 and 15 extending from the front surface 3 and the back surface 5 to the depths t and t ′ respectively. Characterized by an obvious area (denuded zone). Between the oxygen precipitate-free regions 15 and 15 ', there is a region 17 having a non-uniform oxygen precipitate concentration profile having a profile that depends on the pore profile as described above.

The concentration of oxygen precipitates in region 17 is primarily a function of the heating process and secondarily a function of the cooling rate. In general, the concentration of oxygen precipitates increases with increasing annealing time and temperature in the heating step, and a precipitate density in the range of about 1 × 10 ⁷ to about 5 × 10 ¹⁰ precipitates / cm ³ is usually obtained. It is done.

  The depths t and t ′ of the oxygen precipitate-free material (denuded zone) 15 and 15 ′ from the front surface 3 and the back surface 5, respectively, are mainly due to the relative movement of the crystal lattice vacancies in the silicon. It is a function of the cooling rate through the resulting temperature range. In general, depth t, t ′ increases with decreasing cooling rate and is at least about 10 micrometers, about 20 micrometers, about 30 micrometers, about 40 micrometers, about 50 micrometers, about 70 micrometers, or In some cases a denuded zone depth is obtained which can even reach about 100 micrometers. Importantly, the depth of the denuded zone is essentially independent of the details of the manufacturing process of the electronic device, and in addition to the conventional out-diffusion of oxygen. It is not dependent. However, as a practical matter, the cooling rate required to obtain a shallow denuded zone depth is somewhat excessive and can cause the risk of wafer shattering due to thermal shock. Thus, alternatively, the thickness of the denuded zone can be controlled by selection of the atmosphere in which the wafer is annealed (as described above) while cooling the wafer at a rate less than excessive. In other words, for a given cooling rate, for a deep denuded zone (eg 50+ microns), for an intermediate denuded zone (eg 30-50 microns), a shallow denuded zone (eg about 30). The atmosphere in which the template for the submicron) or the template without the denuded zone is formed can be selected. With respect to the exact conditions for the annealing and cooling process, the conditions may be other than those described herein without departing from the scope of the present invention. Further, such conditions adjust, for example, the duration and temperature of annealing and the atmospheric conditions (ie, atmospheric composition and oxygen partial pressure) to optimize the desired depth t and / or t ′. Can be obtained experimentally.

  The rapid thermal process used in the method of the present invention causes a small amount of oxygen out-diffusion from the front and back surfaces of the wafer, since the extent of the outdiffusion causes a denuded zone. This is significantly less than that observed in conventional methods. As a result, the ideal deposition wafer of the present invention has a substantially uniform self-interstitial oxygen concentration as a function of distance from the silicon surface. For example, prior to the oxygen precipitation heat treatment, the wafer is moved from the center of the wafer to a region of the wafer within about 15 microns of the silicon surface, more preferably from the center of the silicon to about 10 microns of the silicon surface. Self-interstitial to the region, even more preferably from the center of the silicon to the region of the wafer within about 5 microns of the silicon surface, and most preferably from the center of the silicon to the region of the wafer within about 3 microns of the silicon surface It will have a substantially uniform concentration of oxygen. Here, the substantially uniform oxygen concentration means that the fluctuation of the oxygen concentration is about 50% or less, preferably about 20% or less, and most preferably about 10% or less.

  In general, the oxygen precipitate heat treatment does not cause a substantial amount of oxygen out-diffusion from the heat-treated wafer. As a result, the concentration of self-interstitial oxygen in the denuded zone at distances greater than a few microns from the wafer surface does not change much as a result of the precipitate heat treatment. For example, if the wafer's denuded zone consists of the area of the wafer between the surface of the silicon and a portion of distance D (which is at least 10 micrometers) as measured from the front surface toward the central plane, silicon The oxygen concentration at a location in the denuded zone at a distance equal to half the distance D from the surface will generally be at least about 75% of the peak concentration of the self-interstitial oxygen concentration in any part of the denuded zone. . For some oxygen precipitation heat treatments, the self-interstitial oxygen concentration at this location is somewhat higher, at least 85%, at least 90%, or even at least 95% of the highest oxygen concentration in the denuded zone. Can be.

E. Epitaxial Layer In one embodiment of the present invention, an epitaxial layer can be deposited on the surface of an ideally deposited wafer. The oxygen precipitate nucleation and stabilization process of the present invention as described above can be performed either before or after epitaxial deposition (or epitaxial growth). By generating stabilized oxygen precipitation nucleation centers, the epitaxial deposition process can be carried out without dissolving the introduced precipitate profile.

Epitaxial layers are known in the art and are used by those skilled in the art in the deposition of vapor phase silicon-containing compositions. In a preferred embodiment of the invention, the surface of the wafer is exposed to an atmosphere containing a volatile gas containing silicon (silicon) (eg, SiCl ₄ , SiHCl ₃ , SiH ₂ Cl ₂ , SiH ₃ Cl and SiH ₄ ). It is also preferred that the atmosphere contains a carrier gas (preferably H ₂ ). In one embodiment, the silicon source during epitaxial deposition is SiH ₂ Cl ₂ or SiH ₄ . When using SiH ₂ Cl ₂ , the reactor vacuum during deposition is preferably from about 500 Torr to about 760 Torr. On the other hand, if SiH ₄ is used, the reactor is preferably about 100 Torr. Most preferably, the silicon source during deposition is SiHCl ₃ . In this case, the cost can be lower than when other silicon sources are used. Furthermore, epitaxial deposition using SiHCl ₃ can also be performed at atmospheric pressure. This is advantageous because it eliminates the need for a vacuum pump and eliminates the need to be robust to prevent crushing of the reaction chamber. Furthermore, the risk of impairing safety is reduced, and the risk of air or other gas leaking into the reaction chamber can be reduced.

During epitaxial deposition, the wafer surface is at least about 800.degree. C., more preferably about 900.degree. C., most preferably sufficient to prevent polycrystalline silicon from depositing on the wafer surface by an atmosphere containing silicon. Is preferably maintained at about 1100 ° C. The growth rate of the epitaxial deposition is preferably about 0.5 to about 7.0 μm / min. For example, by using an atmosphere consisting essentially of about 2.5 mol% SiHCl ₃ and about 97.5 mol% H ₂ at a temperature of about 1150 ° C. and a pressure of about 1 atm, about 3.5-4 A speed of 0.0 μm / min can be achieved.

If desired, the epitaxial layer can further include a p-type or n-type dopant. For example, it may be preferred that the epitaxial layer contains boron. Such a layer can be formed, for example, by including B ₂ H ₆ in the atmosphere during deposition. The molar fraction of B ₂ H ₆ in the atmosphere used to obtain the desired properties (eg, resistivity) depends on several factors, such as boron from a particular substrate during epitaxial deposition. It will depend on the extent of out-diffusion, the amount of p-type and n-type dopants present in the substrate and reactor as contaminants, and the pressure and temperature of the reactor. For high resistivity applications, the dopant concentration in the epitaxial layer should be as low as practical.

F. Fabrication of silicon-on-insulator structures The stabilization of oxygen precipitation nuclei by nitrogen / carbon doping of the present invention is described in US Pat. No. 6,236,104, the disclosure of which is incorporated herein by reference. Can also be used to fabricate silicon-on-insulator (SOI) structures such as those disclosed in SOI structures can be manufactured by subjecting a base wafer or handle wafer to standard ion implantation processes in the art (see, for example, US Pat. No. 5,436,175). It is preferable to perform an ideal deposition wafer process on the handle wafer prior to the ion implantation process that produces an oxide layer located within the denuded zone.

  Alternatively, after bonding the device layer wafer to a nitrogen / carbon doped stabilized handle wafer to the device layer wafer, wafer thinning techniques (eg, well known in the art) (eg, US Pat. No. 5,024,723) can be used to fabricate SOI structures by etching away portions of the device layer wafer. It is preferable to bond the device layer wafer to the handle wafer after subjecting the nitrogen / carbon doped handle wafer to an ideal deposition wafer process. Alternatively, however, the device layer wafer can be first bonded to a nitrogen / carbon doped handle wafer to subject the entire SOI structure to an ideal deposition wafer process.

  In addition to nitrogen / carbon stabilization, disclosed in US Patent Application No. 60 / 300,208, filed June 22, 2001, the disclosure of which is incorporated herein by reference. The stabilization of the oxygen precipitation nucleation center can be further improved by the thermal stabilization process.

G. Measurement of crystal lattice vacancies Measurement of crystal lattice vacancies in single crystal silicon can also be performed by platinum diffusion analysis. In general, the diffusion time and temperature are preferably chosen so that the Frank-Turnbull mechanism predominates for platinum diffusion, but is sufficient to reach a steady state of vacancy decoration with platinum atoms. Is deposited on the sample and diffused within the horizontal surface. For wafers with vacancy concentrations typical of the present invention, a diffusion time of 20 minutes can be used at a temperature of 730 ° C., but more accurate tracking can be achieved at a lower temperature, eg, about 680 ° C. Is observed to be able to. Furthermore, in order to minimize the effects that can be caused by the silicidation process, the platinum deposition method preferably produces a surface concentration of one monolayer or less. Platinum diffusion techniques are described, for example, in Jacob et al., J. Appl. Phys., Vol. 82, p. 182 (1997); Zimmermann and Ryssel, “The Molding of Platinum Diffusion in Silicon Under Non-Equilibrium Conditions” J. Electochemical Society. , vol 139, p. 256 (1992); Zimmermann, Goesele, Seilenthal and Eichiner, “Vacancy Concentration Wafer Mapping in Silicon”, Journal of Crystal Growth, vol. 129, p. 582 (1993); Zimmermann and Flaster, “Investigation of the Nucleation of Oxygen Precipitates in Czochralski Silicon At Any Early Stage '' Appl. Phys. Lett., vol. 60, p. 3250 (1992); and Zimmermann and Ryssel, Appl. Phys. Lett., vol. 55, p. 121 (1992).

  It should be understood that the above description is intended to explain the present invention and is not intended to limit the present invention. Many embodiments will be apparent to those of skill in the art upon reading the above description. Therefore, the scope of the invention should not be determined only by referring to the above description, but should be determined based on the matters described in the claims and matters equivalent to the descriptions. is there.

FIG. 2 is a schematic diagram of the method of the present invention.

Claims (45)

One is the front surface of the wafer and the other is the back surface of the wafer, and includes two generally parallel main surfaces, a central plane between the front and back surfaces, and the front and back surfaces. A single crystal silicon wafer having an outer peripheral edge to communicate with,
The wafer comprises a dopant selected from the group consisting of nitrogen and carbon, the concentration of the dopant when cooling the wafer from the first temperature T ₁ to a second temperature T ₂ at a rate R, stable The stabilized oxygen precipitation nucleation center has a concentration sufficient to promote the formation of the oxygen precipitation nucleation center, and the stabilized oxygen precipitation nucleation center cannot be dissolved at a temperature of 1150 ° C. or less. It can melt at a temperature in the range of 1300 ° C., the temperature T ₁ is in the range of about 1150 ° C. to about 1300 ° C., and the temperature T ₂ is a temperature at which crystal lattice vacancies cannot move relatively in silicon. The rate R is at least about 5 ° C./second;
The surface layer having a region of the wafer between the portion of distance D and the front surface, measured from the front surface towards the central plane, does not have a stabilized oxygen precipitation nucleation center; A single crystal silicon wafer wherein the bulk layer having the second region of the wafer between the central plane and the surface layer has a stabilized oxygen precipitation nucleation center. The single crystal silicon wafer of claim 1, wherein the dopant is nitrogen and the concentration of nitrogen ranges from about 1 x 10 ¹² to about 5 x 10 ¹⁴ atoms / cm ³ . The single crystal silicon wafer of claim 1, wherein the dopant is nitrogen and the concentration of nitrogen in the wafer ranges from about 1 x 10 ¹² to about 1 x 10 ¹³ atoms / cm ³ . Dopant is carbon, single crystal silicon wafer of claim 1 wherein the concentration of carbon in the range of about 1 × ^{10 16} ~ about 4 × ^{10 17} atoms / cm ^3. Dopant is carbon, single crystal silicon wafer of claim 1 wherein the concentration range of about 1.5 × ^{10 16} ~ about 3 × ^{10 17} atoms / cm ³ of carbon in the wafer.   The single crystal silicon according to claim 1, wherein the stabilized oxygen precipitation nucleation center in the bulk layer has a concentration profile in which the peak concentration exists at or near the center plane and decreases as a whole toward the front surface of the wafer. Wafer.   The single crystal silicon wafer according to claim 1, wherein the stabilized oxygen precipitation nucleation center in the bulk layer has a concentration profile in which the peak density is in a specific portion between the central plane and the surface layer.   The single crystal silicon wafer of claim 1, wherein the distance D is at least about 10 micrometers.   The single crystal silicon wafer of claim 1, wherein the distance D is at least about 20 micrometers.   The single crystal silicon wafer of claim 1, wherein the distance D is at least about 50 micrometers.   The single crystal silicon wafer of claim 1, wherein the distance D is in the range of about 30 to about 100 micrometers.   The single crystal silicon wafer according to claim 1, wherein the wafer has an epitaxial layer on at least one surface thereof. The single crystal silicon wafer of claim _{1, wherein the} temperature T1 is at least about 1150C. The single crystal silicon wafer according to claim _{1, wherein the} temperature T1 is in the range of about 1200C to about 1300C.   The single crystal silicon wafer according to claim 1, wherein the rate R is at least 10 ° C / second.   The single crystal silicon wafer according to claim 1, wherein the rate R is at least 20 ° C / second.   The single crystal silicon wafer according to claim 1, wherein the rate R is at least 50 ° C / second. One is the front surface of the wafer and the other is the back surface of the wafer, and includes two generally parallel main surfaces, a central plane between the front and back surfaces, and the front and back surfaces. A single crystal silicon wafer having an outer peripheral edge to communicate with,
The wafer comprises a dopant selected from the group consisting of nitrogen and carbon, and when nitrogen is the dopant, the concentration of nitrogen ranges from about 1 × 10 ¹² to about 5 × 10 ¹⁴ atoms / cm ³ . When carbon is the dopant, the concentration of carbon ranges from about 1 × 10 ¹⁶ to about 4 × 10 ¹⁷ atoms / cm ³ ;
The surface layer having a region of the wafer between the portion of distance D and the front surface, measured from the front surface towards the central plane, does not have a stabilized oxygen precipitation nucleation center; A single crystal silicon wafer wherein the bulk layer having a second region of the wafer between the central plane and the surface layer has a stabilized oxygen precipitation nucleation center. One is the front surface of the wafer and the other is the back surface of the wafer, and includes two generally parallel main surfaces, a central plane between the front and back surfaces, and the front and back surfaces. contact has an outer edge which, comprises a dopant selected from a group consisting of nitrogen and carbon, the concentration of the dopant, the rate R of the wafer from the first temperature T ₁ to a second temperature T ₂ When cooled at a temperature sufficient to promote the formation of stabilized oxygen precipitation nucleation centers, and the stabilized oxygen precipitation nucleation centers cannot be dissolved at a temperature of 1150 ° C. or lower. However, it can melt at temperatures in the range of about 1150 ° C. to about 1300 ° C., temperature T ₁ is a temperature in the range of about 1150 ° C. to about 1300 ° C., and temperature T ₂ At a temperature that cannot move Yes, the speed R is at least about 5 ° C./second, and further comprises a region of the wafer between the front surface and a portion of the distance D as measured from the front surface toward the center plane for stabilization. And a bulk layer having a stabilized oxygen precipitation nucleation center having a second region of the wafer between the central plane and the surface layer. A single crystal silicon handle wafer comprising:
A silicon-on-insulator structure having a single crystal silicon device layer; and an insulating layer between the handle wafer and the device layer. A method of manufacturing a single crystal silicon wafer having controlled oxygen precipitate behavior comprising:
A wafer sliced from a single crystal silicon ingot grown by the Czochralski method, measured at the front surface, the rear surface, the central plane between the front surface and the rear surface, and measured from the front surface toward the central plane A front surface layer having a region of the wafer between the portion of distance D and the front surface, a bulk layer having a region of the wafer between the center plane and the front surface layer, and selected from the group consisting of nitrogen and carbon The dopant concentration is such that when the wafer is cooled from the _first temperature T ₁ to the second temperature T ₂ at a rate R, the formation of stabilized oxygen precipitation nucleation centers is achieved. The concentration is sufficient to promote and stabilized oxygen precipitation nucleation centers cannot dissolve at temperatures below 1150 ° C., but should dissolve at temperatures in the range of about 1150 ° C. to about 1300 ° C. Can, temperatures T ₁ is a temperature in the range of about 1150 ° C. ~ about 1300 ° C., temperature T ₂ is the temperature at which crystal lattice vacancies are not relatively moved in silicon, the rate R of at least about 5 ° C. / Selecting a wafer that is seconds;
Heating the wafer to a temperature of at least about 1150 ° C. to produce crystal lattice vacancies in the front surface layer and the bulk layer;
In the heated wafer, the vacancy peak density is present in the bulk layer, and the concentration decreases as a whole from the position of the wafer peak density toward the front surface of the wafer, and the vacancy concentration and bulk in the front surface layer are reduced. The difference from the vacancy concentration in the layer is such that the stabilized oxygen precipitation nucleation center is not formed in the front surface layer, but the stabilized oxygen precipitation nucleation center is formed in the bulk layer. Cooling the concentration profile at a rate that produces it in the wafer; and, when cooling the heated wafer, the concentration of stabilized oxygen precipitation nucleation centers in the bulk layer depends primarily on the concentration of the vacancies. Producing a stabilized oxygen precipitation nucleation center in the bulk layer. 21. The method of claim 20, wherein the dopant is nitrogen and the concentration of nitrogen in the wafer is from about 1 x 10 < ¹² > to about 5 x 10 < ¹⁴ > atoms / cm < ³ >. 21. The method of claim 20, wherein the dopant is nitrogen and the concentration of nitrogen in the wafer is from about 1 x 10 < ¹² > to about 1 x 10 < ¹³ > atoms / cm < ³ >. 21. The method of claim 20, wherein the dopant is carbon and the concentration of carbon in the wafer is from about 1 x 10 < ¹⁶ > to about 4 x 10 < ¹⁷ > atoms / cm < ³ >. 21. The method of claim 20, wherein the dopant is carbon and the concentration of carbon in the wafer is from about 1.5 x 10 < ¹⁶ > to about 3 x 10 < ¹⁷ > atoms / cm < ³ >.   The method of claim 20, wherein the wafer is heated to a temperature of at least about 1175 ° C.   21. The method of claim 20, wherein the wafer is heated to a temperature of at least about 1200 degrees Celsius.   The method of claim 20, wherein the wafer is heated to a temperature of at least about 1200C to about 1275C.   21. The method of claim 20, wherein the wafer is exposed to an atmosphere comprising one or more gases selected from the group consisting of argon, helium, neon, carbon dioxide, and nitrogen or a nitrogen-containing gas while heating.   30. The method of claim 28, wherein the atmosphere comprises argon.   30. The method of claim 28, wherein the atmosphere comprises nitrogen or a nitrogen-containing gas.   29. The method of claim 28, wherein the atmosphere comprises argon and nitrogen or a nitrogen containing gas.   30. The method of claim 28, wherein the atmosphere has a partial pressure of oxygen of about 0.01 atmospheres or less.   30. The method of claim 28, wherein the atmosphere has a partial pressure of oxygen of about 0.005 atmospheres or less.   30. The method of claim 28, wherein the atmosphere has a partial pressure of oxygen of about 0.002 atmospheres or less.   30. The method of claim 28, wherein the atmosphere has a partial pressure of oxygen of about 0.001 atmospheres or less.   30. The method of claim 28, wherein the atmosphere has a partial pressure of oxygen of about 0.0001 to 0.01 atmospheres or less.   30. The method of claim 28, wherein the atmosphere has a partial pressure of oxygen of about 0.0002 to 0.001 atmospheres or less.   The front surface of the wafer is exposed to a first atmosphere while heating, and the first atmosphere is one or more selected from the group consisting of argon, helium, neon, carbon dioxide and nitrogen or a nitrogen-containing gas. And comprising exposing a back surface of the wafer to a second atmosphere while heating, wherein the second atmosphere is from the group consisting of argon, helium, neon, carbon dioxide and nitrogen or a nitrogen-containing gas. 21. The method of claim 20, comprising one or more selected gases, wherein the first atmosphere and the second atmosphere include at least one non-common gas.   Prior to the heat treatment that produces crystal lattice vacancies, the wafer is heated to a temperature of at least about 700 ° C. in an oxygen-containing atmosphere to form a surface silicon dioxide layer that can function as a sink for the crystal lattice vacancies. 21. The method of claim 20, wherein:   21. The method of claim 20, wherein the cooling rate is at least about 5 [deg.] C / sec through a temperature range in which the crystal lattice vacancies can move relatively within the silicon.   21. The method of claim 20, wherein the cooling rate is at least about 20 ° C./second through a temperature range in which the crystal lattice vacancies can move relatively within the silicon.   21. The method of claim 20, wherein the cooling rate is at least about 50 ° C./second through a temperature range in which the crystal lattice vacancies can move relatively within the silicon.   21. The method of claim 20, wherein the cooling rate is at least about 100 ° C./second through a temperature range in which the crystal lattice vacancies can move relatively within the silicon.   21. The method of claim 20, comprising depositing an epitaxial layer on at least one surface of the wafer after the stabilized oxygen precipitation nucleation centers are formed in the bulk layer. A method of manufacturing a single crystal silicon wafer having controlled oxygen precipitate behavior comprising:
A wafer sliced from a single crystal silicon ingot grown by the Czochralski method, measured at the front surface, the rear surface, the central plane between the front surface and the rear surface, and measured from the front surface toward the central plane A front surface layer having a region of the wafer between the portion of distance D and the front surface, a bulk layer having a region of the wafer between the center plane and the front surface layer, and selected from the group consisting of nitrogen and carbon The concentration of nitrogen is in the range of about 1 × 10 ¹² to about 5 × 10 ¹⁴ atoms / cm ³ , and when carbon is the dopant, Selecting a wafer whose concentration ranges from about 1 × 10 ¹⁶ to about 4 × 10 ¹⁷ atoms / cm ³ ;
Subjecting the wafer to a heat treatment to produce crystal lattice vacancies in the bulk layer and the front surface layer;
In the heated wafer, the vacancy peak density is present in the bulk layer, and the concentration decreases as a whole from the position of the wafer peak density toward the front surface of the wafer, and the vacancy concentration and bulk in the front surface layer are reduced. The difference from the vacancy concentration in the layer is such that the stabilized oxygen precipitation nucleation center is not formed in the front surface layer, but the stabilized oxygen precipitation nucleation center is formed in the bulk layer. Cooling the concentration profile at a rate that produces it in the wafer; and, when cooling the heated wafer, the concentration of stabilized oxygen precipitation nucleation centers in the bulk layer depends primarily on the concentration of the vacancies. Producing a stabilized oxygen precipitation nucleation center in the bulk layer.

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