TW200305932A - Ideal oxygen precipitating silicon wafers with nitrogen/carbon stabilized oxygen precipitate nucleation centers and process for making the same - Google Patents

Abstract

A silicon wafer having a controlled oxygen precipitation behavior such that a denuded zone extending inward from the front surface and oxygen precipitates in the wafer bulk sufficient for intrinsic gettering purposes are ultimately formed. Specifically, prior to formation of the oxygen precipitates, the wafer bulk comprises dopant stabilized oxygen precipitate nucleation centers. The dopant is selected from a group consisting of nitrogen and carbon and the concentration of the dopant is sufficient to allow the oxygen precipitate nucleation centers to withstand thermal processing such as an epitaxial deposition process while maintaining the ability to dissolve any grown-in nucleation centers.

Description

(1) 200305932 发明, description of the invention (the description of the invention should state: the previous technical field, prior technology, content, embodiment, and drawings of the invention are briefly explained) The summary of the present invention β is used to manufacture electronic address conductor materials The preparation of the substrate, especially the kind of Shixi processing, is true. In summary, the invention relates to the ideal non-uniform depth distribution of wafers A and γ during the heat treatment% period of any electronic device process on the shell. 4Semiconductor electronics, single crystal silicon, which is the starting material for most of the process, is usually configured by the Czochralski method, in which the single seed crystal ^ ^ Θ H is slowly extracted Generated. In the lava stone, it is in the midst of misfortune, that is, it is combined with various miscellaneous, 3, and 4 miscellaneous species, which is mainly mixed with oxygen. Oxygen enters the crystal lattice on the molten crystal: again, until it reaches the crystal The solubility of oxygen at mid-melt temperature is based on the concentration determined by the actual segregation coefficient of oxygen in siliconized silicon. This is equal to the degree of dissolution of oxygen in solids at the standard temperature of the electronic device manufacturing process. When the autogenous body is formed and cooled, the solubility of oxygen in it is rapidly reduced, and the oxygen is in a supersaturated concentration. The heat treatment cycle usually used for the coating of buns can cause oxygen in silicon wafers. ^ Deposition reaches oxygen supersaturation. The harmful or beneficial end of the deposit depends on its position on the wafer. The oxygen deposit is damaged in the active device area of the wafer, and it is operated. It is on the wafer. Oxygen deposits in the main body can trap metal impurities that are not beneficial to the crystal and contact. The use of oxygen deposits in the body of the wafer to capture the metal is commonly referred to as internal or intrinsic absorption impurities (IG). The process of the I-I process involves a series of steps designed to produce silicon. There is no area on the surface of Q ΓΞΓ 无, L Oxygen deposits (commonly referred to as bare or no-deposit areas). The remaining body of the wafer contains sufficient oxygen deposits for internal absorption of impurities (2) 200305932. The exposed areas can be formed in high spring and high heat sequence, such as: ⑷ Oxygen diffusion heat treatment for at least four hours in an inert environment at high temperature (more than 1,100 degrees Celsius); formation of oxygen nucleation at high temperature (from six hundred degrees Celsius to seven hundred and fifty degrees Celsius), and (C) at high temperature (1,000 degrees Celsius to 1,150 degrees Celsius) oxygen ⑶〇2) the birth of the sediment A. Please refer to F. Shimura Jun, Ac-Second Press, San Diego, California, 1989, Semiconductor Dream Crystal Technology, , The milk page and the reference materials listed therein. However, the process of accessing advanced electronic devices such as dynamic random access memory has begun to minimize the use of high temperature methods. Although some processes retain sufficient South temperature methods In order to produce sufficient density in the exposed area and a large number of deposits, the material tolerance is too tight to provide commercial products. Other current highly advanced electronic device processes do not include an external diffusion step. Because of the oxygen deposits in the active device area, Related issues' Thus such electronic device manufacturers must use Shixi wafers where no oxygen deposits are formed anywhere in the wafer under the conditions of the soybean process. As a result, all the inherent ability to absorb impurities is lost. &Quot; Inventiveness 衮Therefore, in the purposes of the present invention, a single wafer is provided, and during the heat treatment cycle of any electronic device process, the distribution of the depth of the uneven deposition of oxygen will be formed; providing such a wafer will be optimized and recoatable The formation of exposed areas with sufficient depth and full dense production in the wafer body provides such wafers, where the formation of the exposed areas and the "heart = of =" are not related to the difference in oxygen concentration in the wafer area; provide this I: The thickness of 20% of the exposed area is essentially independent of the integrated circuit manufacturing process, and the field is not provided; wafers of this type are provided, in which the exposed area of the wafer body and oxygen (3) (3) 200305932 i product The formation of the crystal is not affected by the thermal process and oxygen concentration of Cheklaussky's production of single crystals. 'Wafer system is a method of cutting from the single crystal, in which the formation of the exposed area does not depend on diffusion outside oxygen. Determination :, = = Method 'The cut is doped with sufficient concentration of nitrogen and / or carbon to stabilize the nucleation center of the oxygen deposits, and the perch is for you " ^, to make this Cheng Wen subsequent rapid heat treatment Without hindering the formation of the exposed area. In short, the present invention is directed to a single crystal `` circle '' with two major, substantially parallel surfaces, one of which is the front surface of the wafer and the other is the rear surface of the wafer. The center plane between the rear surfaces is different, and the peripheral edge of the front and back surfaces is joined. The surface layer includes the front surface and the wafer area measured at least about 10 microns from the front surface to the center plane. The second region of the wafer between the plane and the first region. This wafer also has: The unevenness of the nucleation center of the sediment may be formed by the U's knife cloth, that is, the k-degree of the center of the oxygen deposit in the main layer is greater than the concentration of the nucleation center of the oxygen deposit in the surface layer. The core of the ::: f core has a -concentration cross-section curve, and the density of the oxygen deposits in the center of # is at or near the central plane, and the concentration follows the front surface of the wafer from the peak duty position. Μ ^ ^ decreases. On the same date, the wafer contains a pine material selected from the group consisting of nitrogen, trans, or a combination thereof. When a nitrogen dopant is used, the nitrogen concentration is about 1 彳 ⑴2 $ / — 10 to about 5 x 1014 atoms. The concentration of carbon is between the parent cubic centimeters < 1016 and about 4 x 1017 atoms. The present invention is also directed to a second method of single-crystal silicon with zero g? 1 m ^ i equipped with controlled oxygen deposition. This method includes the selection of single crystals produced by the Cheklaussky method = cutting and containing- The front surface and the rear surface and between the front and back surfaces-the central plane says "This wafer does not contain a front surface layer, a main body layer and dopants; front (4) 200305932 second surface layer: the rigid surface and from the front surface to The distance measured between the central planes: the wafers between them; the body layer covers the t-round area between the central plane and the front surface layer; and the dopant is selected from the combination of nitrogen and carbon. When the dopant is a rat, Its concentration is about 1 x 1012 to about 5 x 1014 atoms per cubic centimeter. When the dopant is carbon, its concentration is about ΐxΐ〇6 to about 4 cents per 7 centimeters of original I. The selected wafer is heated to about 150 degrees Celsius to form lattice vacancies in the first two and the main layer. The heated wafer is quickly cooled to 5JI 哉% # in the wafer, where the density of boxing vacancy is at the main layer # and the wideness of the value is roughly decreased according to the direction of the front surface of the wafer, and the front deposits The nucleation center, the oxygen deposit formed the oxygen nucleation accretion nucleation center formed in the main layer. And when the heated wafer cools down, the nucleation center of the lice deposit that is 士% 疋 is formed in the middle of the day, and the stable oxygen in the main layer mainly depends on the concentration ㈣. The concentration of the accumulation nucleation center of the present invention will be further described in accordance with the present invention. According to the present invention, a micro-deposited wafer has been issued during practically any electronic device manufacturing process. There are only intrinsically absorbing impurities with the right eight hearts & the dew area that fills the knife's ice and the aa round body with θ π degree oxygen deposits. This-is formulated in a moment. This method creates a general method for oxygen deposition during the electronic device manufacturing process. "Identify or" print "the original material of the ideal deposited wafer. This is based on R ?, traditional Cek The single crystal dream wafer cut from the single crystal ingot produced by the Rao body generation method. (5) (5) 200305932

These methods, as well as standard silicon slicing, grinding, etching and polishing techniques, are described in "Semiconductor Silicon Crystal Technology" by F. shimura, Academicim Press, 1989, and "Shi Xi Chemical Etching in Springer_Verlag, New York, 1982," (J_ ed.), Recorded here for reference. The silicon produced by the Cheklauszki method usually contains an oxygen concentration in the range of about 5x10 " to about 9x10i7 atoms per cubic centimeter (ASTM standard F_i2i_83). Because Oxygen deposition essentially exhibits the degeneration of oxygen concentration from ideally deposited wafers. Therefore, the original wafer may have oxygen concentrations within or outside the range obtained by the Cheklaussky method. The refining point (approximately 1410 degrees Celsius) can be formed in a single crystal silicon ingot cut by a wafer with a cooling rate ranging from approximately 750 degrees to approximately 350 degrees Celsius. Original The existence of such nucleation centers in the material is irrelevant to the present invention, but these centers can be decomposed by heat treatment of silicon at a temperature of about 1,300 degrees Celsius. Some heat treatments such as silicon are at about 80 degrees Celsius. Four hours and so on, these centers can be stabilized so that they do not decompose below about 1,150 degrees Celsius. The detection limit of oxygen deposits is currently about 5 x 106 deposits per cubic centimeter. Oxygen precipitation 2 The existence of a nucleation center (or the density cannot be measured directly using existing technologies. However, various technologies can be used to detect its existence indirectly. As mentioned earlier, the nucleation center of oxygen deposits in silicon can be thermally treated by oxygen deposition of silicon. It is stable and deposits can be formed at these locations. Therefore, these nucleation centers can be measured indirectly after the oxygen deposition heat treatment, such as annealing the wafer at eight degrees Celsius for four hours, and then annealing at sixteen degrees Celsius for sixteen Heat treatment for hours. Now please refer to Figure 丨, the original material of the ideal deposited wafer of the present invention is a single crystal -10- (6) 200305932 :::: having a different surface 3 'rear surface 5 and a front and rear surface hypothesis: Central plane 7. In this article, "front" and "," later, the words are used to distinguish the wafer's "mainly substantially the same as the flat surface". The term used for the front surface of the wafer is not necessarily = then the electronic device is manufactured in it On the surface, and The term "surface after wafer picking" does not refer to the main surface of the wafer torpedo + resident & + UI /, the surface on which the electronic clothing is located. In addition, because Shi Xi wafers usually have some changes in total thickness, such as protruding bending, etc. Therefore, the midpoint between each point on the front surface and each point on the rear surface may not be on the same accurate plane; but in fact, the total thickness of the f-curve usually varies very little. Approximately, the midpoints can be described as imaginary. The center is the equal distance β χ + between the front and rear surfaces. In the first specific shot of the method of the present invention, the wafer is heat-treated in a milk-containing environment in step ^ to generate a surface oxide layer surrounding the wafer i.-General In terms of the thickness of the oxide layer is greater than that of the native oxide layer (about 15 angstroms) formed on the stone, the thickness of the oxide layer is at least about-+ apricot husks, about 10 angstroms, and in some specific | At least about twenty-five Angstroms or even about thirty Angstroms. What has been obtained so far: Evidence suggests that an oxide layer greater than about thirty angstroms, while not interfering with the desired effect, will not provide additional benefits. In step \ 'wafer is subjected to heat treatment', in which the wafer is heated to a high temperature to form lattice vacancies 13 in wafer 1 and increase the vacancy number density. The processing step is suitable to be implemented in a rapid thermal annealing machine. Heating to the target temperature and annealing at that temperature for a short period of time.-In general, the temperature that the Japanese yen will withstand is at least 1,150 degrees Celsius, and preferably at least -175 degrees Celsius, More preferably at least about 12 hundred Baidu, and more preferably _12 Baidu to 1,275 degrees. -11-(7) 200305932

Male, not) section curve. According to the experimental evidence obtained in item 4, it is best that the environment in the rapid thermal annealing step contains a small amount of pressure of oxygen, water vapor and other oxidizing gases, that is, the environment is free of oxidizing gas or the pressure of these gases, which is not enough to inject Self-filled vacant atoms in silicon that suppress vacancy concentration build-up. Although the lower limit of the oxidizing gas concentration has not yet been determined, it has been shown that the partial pressure of oxygen at atmospheric pressure or parts per million parts per million (ppma) does not increase the vacancy concentration and has no effect. Therefore, the pressure of oxygen or other oxidizing gas contained in the environment should be less than (001) atmospheric pressure (10,000 ppma), preferably not more than about 5,000 atmospheric pressure (5,000 ppma), and about 0 ·· 002 or about 0.0000 atm (2, 000 or 10,000 ppma) is more preferred. In addition to the formation of lattice vacancies in the rapid thermal annealing step, the nucleation centers of unstable radon gas deposits in the silicon raw material also decompose. These nucleation centers may be formed during the generation of single crystal silicon ingots from diced wafers, or other occasions due to previous thermal history of the wafers or silicon ingots. Therefore, as long as these centers can be decomposed during the rapid thermal annealing step, it does not matter whether they exist in the original material. Rapid thermal annealing can be performed in any commercial rapid thermal annealing furnace, including wafers -12- 200305932

(8) Individual heating by high-power lamp bars. The rapid thermal annealing furnace can quickly heat the Shixi wafer, for example, the wafer is heated from room temperature to 1,200 degrees Celsius in a few seconds. One of these commercial rapid thermal annealing furnaces is a Model 610 furnace, manufactured by AG Associate (Mountain View, California).

Intrinsic point defects (vacancies and self-filled vacancies) can diffuse through monocrystalline silicon, and the rate of diffusion depends on the temperature. The intrinsic point defect is therefore a function of the intrinsic defect diffusion rate 'and the recombination rate is a function of temperature. For example, the intrinsic point defect moves near the annealing temperature in the wafer rapid thermal annealing step, and it does not move substantially at any practical time in the business world on Qibaidu. The experimental evidence obtained so far is not at a temperature below seven hundred degrees Celsius, and the effective diffusion of vacancies is greatly slowed down. "Even when the temperature is as high as eight hundred degrees Celsius, nine hundred degrees Celsius or one thousand degrees, it is believed that" it will not move in any practical period of business . After step S2 is completed, the wafer is rapidly cooled from the lattice space in the single crystal silicon relative to the T-movement temperature range in step \. When the temperature of the wafer decreases through this temperature range g, the vacancies diffuse to the oxide layer 9 and tend to annihilate, resulting in a change of vacancy = degree break = medium. The degree of change depends on the length of the wafer a 1 at the temperature within the range. set. If the wafer is in this range, the temperature will be infinitely long at 5 o'clock. The concentration of vacancies in the wafer body 11 will be roughly equal again, and the concentration will be large! It is less than the equilibrium value of the lattice vacancy concentration when the heat treatment step is just completed. But position: quickly ~ but 'can achieve uneven distribution of lattice vacancies. Up to 3 5 near the central plane 7, and the space concentration follows the front surface 3 and the back table ^

3 million decrease. _Funkershan L is at least about an average cooling in the range of ^ ° C per second. ❸ According to the depth of the exposed area, it is better to have at least about 20 ° C per second. X The average cooling rate should be at least about 5 ° C per second- -13-(9) 200305932

It is best to use at least about one Baidu per second. For current applications, about one Baidu to two Baidu per second is the most suitable. Once the wafer is cooled to a temperature where the lattice void is outside the relative movement temperature range of the single crystal silicon, the cooling rate does not affect the deposition characteristics of the wafer so much that it is not extremely important. Conveniently, the cold end step can be performed in the same environment as the heating step. In step S4, the wafer is subjected to an oxygen deposition heat treatment. For example, a wafer can be annealed at eight degrees Celsius for four hours, and then annealed at one thousand degrees Celsius for sixteen hours. It is also advisable to place the wafer in a furnace of about 80 degrees Celsius as the first step of the electronic device process. When placed in a furnace at this temperature, the wafers that had previously been rapidly heat-treated will have compartments with different oxygen deposition. In the vacancy area (the body of the wafer), after the wafer is placed in the furnace, the oxygen quickly gathers. When the load temperature is reached, the clustering process ends and the distribution of clusters is reached, depending on the initial concentration of vacancies. In the low vacancy area (near the wafer surface), the wafer is deposited into a nucleation center with oxygen that is absent before the ##; Also: oxygen accumulation is not significant. When it reaches more than eight hundred degrees Celsius, or if the temperature is two: fixed, the accumulation in the vacant area will generate sediment and be depleted, but it will have no effect in poor mouth. Divide the wafer into various vacancy concentration areas, that is, effectively create a kind of template. The oxygen map determined by placing the wafer in the furnace is shown in Figure 1. The synthetic depth distribution of oxygen deposits in the wafer is determined by The area of oxygen dipeptide material removal (exposed areas) (15, 15,) is extended from the front surface 3 and the rear surface to the ice degree (t, t,) for specialization. In the anaerobic sediment zone ⑴, the region π between them contains oxygen deposits having a substantially uniform density. The concentration of oxygen deposits in the region Π is mainly a function of the heating step, and the secondary -14-200305932 (ίο) is a function of the cooling rate. In short, the concentration of oxygen deposits increases with the temperature rise and annealing time during the heating step, and is based on the density of sediments generally obtained in the range of about 5 x 10 1Q per cubic centimeter. $ Oxygen deposit material (exposed area) (15,15,) respectively from the front and back surface ice degrees (t, mainly the temperature range of the relative movement of lattice vacancies in silicon ^ cooling rate function t.-General In other words, the depth (t, t ') increases as the cooling rate decreases, and the depth of the exposed area is at least about 10, 20, 30, 40, 50, 70 = one hundred microns. Obviously, the depth of the exposed area is roughly It has nothing to do with the manufacturing process of the electronic device, and it has nothing to do with the traditional and practical diffusion of oxygen.

The rapid heat treatment method used in the It invention method will cause a small amount of oxygen 2 to diffuse from the front and back surfaces of the wafer, but the amount of external diffusion is far less than that in the traditional method of forming exposed regions. As such, the ideal deposited wafer of the present invention has a fairly uniform true station oxygen / degree, as a function of distance from the silicon surface. For example, before the heat of oxygen deposition, the "Japanese yen" would have a fairly uniform concentration of oxygen in the vacancies of the cut-off area of about 15 microns from the center of the wafer: It is more suitable for the silicon surface to be about 10 microns, and it is even better to be about 5 microns from the center of Shixi to the surface of the wafer, and about 5 microns from the center of Shixi to the crystal = domain and about 3 microns. . The equivalent oxygen concentration in this article is that the change in the degree of milk is not more than about 50%, preferably not more than 20%, and more preferably not more than 10%. Evening = accumulated heat treatment usually does not cause a large amount of oxygen self-heating wafers. In the exposed area, the filling space of a few micrometers from the wafer surface ^ does not change significantly due to the deposition process. For example, if the exposed area package; te Μ 4 and the wafer area measured from the front surface to the center plane -15- (11) 200305932 two (? At least about ten microns) wafer area, bei 1J From the surface of Shi Xi, etc.-the oxygen concentration at the location of the exposed area at half the distance of D is usually at least-about 75% of the oxygen concentration of the empty space anywhere in the exposed area. For a number of deposition heat treatments, the oxygen concentration in the vacancies at this location will be higher to at least 85 percent, 90, or even 95 percent of the highest oxygen concentration anywhere in the bare-road area. -In the second embodiment of the present invention, a non-nitriding environment is used instead of the nitriding ring environment used in the heating (thermal annealing) and cooling steps of the first embodiment. Permissible non-nitriding atmospheric environments include argon, I, neon, carbides, and other non-oxidizing non-nitriding elements and compound gases, or mixtures of these gases ^ non-nitriding rings; the same is true for brothers Nitriding environment may contain a small part of the oxygen pressure, that is, part of the pressure is less than 0. 01 atmosphere (10, 00 ppma), and preferably less than 0. 005 atmosphere (5,000 Ppma) '* * 002 or 〇 〇 atmospheric pressure (2000/1, surface ppma) is better ° In the third embodiment of the present invention, step (s) (thermal oxidation step) is omitted, so the starting wafer only has an inherent oxide layer . However, when this wafer is annealed in Japan, the effect is different from that seen when a wafer with a thicker oxide layer (increased oxide layer) than the intrinsic oxide layer is annealed in nitrogen. When wafers with an increased oxide layer are annealed in a nitrogen environment, when the annealing temperature is reached, the element yield becomes substantially uniform. In addition, the vacancy concentration does not increase significantly as a function of annealing at a certain annealing temperature. However, if the wafer lacks an oxide layer larger than that inherent, and if the wafer's front and back surfaces are annealed in nitrogen, the vacancy concentration (quantity density) curve of the obtained wafer will have a slightly “U” -shaped cross section. That is, the maximum concentration is within the front and rear surfaces—a -16- (12) 200305932: =, which is fairly constant and small in the entire wafer. The minimum concentration is equal to n. The obtained concentration :: the lack of a fire time in the wafer with an intrinsic oxide layer leads to an increase in the vacancy concentration. ^ Validation evidence—It is further shown that such wafers that do not have an oxide layer larger than the intrinsic layer and the listening layer wafer, the difference between the two functions can be avoided due to the presence of molecular oxygen or another: oxidizing gas in the environment. Here is another example. When a wafer not having an intrinsic oxide layer is annealed in a nitrogen environment containing a small amount of oxygen pressure, the effect of crystal circle is the same as that of a wafer with an increased oxide layer. It is not restricted to any original oxide layer with a thickness greater than that of the intrinsic oxide layer. Therefore, an oxide layer may exist in the original crystal κ, or may be formed during the annealing step by increasing the oxide layer. Therefore, according to the present invention, during the rapid thermal annealing step, the atmospheric environment preferably contains a partial pressure of at least about 0.0001 atmospheres (100 ppma), and more preferably at least about 0 to atmospheric pressure (200 ppma). However, for the reasons mentioned above, the partial pressure of oxygen should not exceed 0.01 atmospheres (10,000 ppma), but preferably less than 5,000 atmospheres (5,000 ppma), and 002 or 0.001 atmospheres ( 2,000 ppma / 1,000 ppma). In other embodiments of the invention, the front and back surfaces of the wafer may be exposed to different environments, each containing one or more nitrided or non-nitrided gases. For example, the rear surface of the wafer may be exposed to a nitriding environment and the front surface may be exposed to a non-gasifying environment. In addition, multiple (2, 3, or more wafers) can be stacked face-to-face and annealed simultaneously; when annealing in this way, the faces that are in face-to-face contact are mechanically protected from environmental influences during annealing. In addition, according to -17- (13) 200305932 used during rapid thermal annealing

ί: And the oxygen concentration profile of the desired wafer, the oxide layer can be formed only on the surface of the desired bare core region of the wafer, such as the front surface of the wafer (3) (see Figure 1). The raw material used in the method of the present invention may be a polished silicon wafer, or a polished and polished wafer without polishing. In addition, wafers can have vacancies or lack of work sites as the main intrinsic point defects. For example, the wafer can be empty or self-filled from the center to the edge, or it can contain a central core of a material that is the main material, and a self-centering symmetrical ring around the material that is mainly self-filled.

If an epitaxial epitaxial layer is to be deposited on an ideal deposition wafer, the method of the present invention can be implemented before or after epitaxial epitaxial deposition. If thorium is carried out before it, it is suitable to use a thermal annealing method after the method of the present invention and before epitaxial epideposition, to describe the nucleation center of oxygen deposits in the circle. However, the thermal annealing method takes a long time (it takes about four hours at about eight degrees Celsius, followed by about ten hours at about one thousand degrees Celsius) 'not only reduces the production volume, but also significantly increases the wafer manufacturing cost. In this way, the method of the present invention can be implemented after epitaxial deposition, but this still requires additional processing steps and increases manufacturing costs. In addition, the nucleation center of oxygen deposits can be stabilized by nitrogen doping of silicon crystals (see Applied Physics of F. Shinmra et al. 48 (3), p. 224 (1986). It is revealed that the oxygen-deposited nuclei of nitrogen-doped μ bodies are It is still L 疋 at about 1,250 degrees Celsius. According to the present invention, the concentration of nitrogen in the silicon crystal must be strictly controlled to achieve stable benefits while maintaining the ability to form exposed areas. If the concentration of nitrogen is too low Time (below the parent cubic centimeter atom) (about 0.2 ppma), the cognitive effect cannot be achieved. On the other hand, if the nitrogen concentration is too high (above about IxlO15 atoms per cubic centimeter) (about 0.02 ppma) ), Then the oxygen formed during the crystal formation-18-200305932 (14) R Kaji Gong 'deposition and nucleation center will not decompose in step & At the same time, if the silicon crystal contains too much nitrogen, it will be in the wafer It will form accumulated defects caused by oxidation (〇ISF), which adversely affects the quality of epitaxial epitaxial wafers (see Japanese Patent Office Publication No. 1999-189493). Oxidation on the surface of silicon wafers causes accumulated defects and other vacancies The defects are different and are not covered by the deposition of epitaxial epitaxial silicon layer 〇isf continues to form in epitaxial epigenetic layers, resulting in internally generated defects commonly referred to as epitaxial epiphyseal accumulated defects. The maximum cross-sectional width of epitaxial epiphysial accumulated defects is measured by laser automatic observation devices with existing detection limits. In other words, the range is from about 0.01 micrometers to about 10 micrometers or more. Therefore, according to the present invention, the nitrogen dopant atom concentration suitable for Shi Xi crystals is about 1 > < 1 () 12 to 5x1q14 atoms (M)卯 mail) 'and about 1x per cubic centimeter to 1x1013 atoms (approximately 2 ppma) more, ^ 7W Do not tick the intervening generation room and / or add nitrogen to the polymer stone Xihua refining compound Dandan Mountain, ,; 丄 >

It is the better method to control the lysate τήζ JL M / heyiwu from the li, zi, and rat to the polymerized lysate. In particular, the amount of nitrogen added to the crystal is rapid, for example, a known thickness ^ lice compound (Sl3N4) layer is deposited on a stone wafer with a known diameter, and it is incorporated into the polysilicon compound. The crucible of silicon is 318 grams. The density of the inner ⑸3N4) is approximately per cubic liter. According to the present invention, the oxygen deposit gas is co-doped to obtain a predetermined value. … Replace lice with carbon, or the concentration of carbon in carbon should be between about 0.2 Ppma to about 4 × 1017 atoms (8 ppma). Irrespective of a specific principle, H is known as t ^ ^ ^, where W is a nitrogen / carbon doped atom to block the diffusion of vacancies in the silicon crystal and pyrolyze the negative / sun-day body t 疋 gas / youji core. In particular, it is known that when generating -19- (15) 200305932

When the crystal is cooled, the vacancy concentration reaches the critical supersaturation level (that is, agglomeration occurs at this point) ', which leads to the formation of vacancy defects or micro-blanks in the agglomeration. For example, ’agglomeration will burst at approximately 1150-1050 ° C. As the crystals cooled, the micro-blank increased because the vacancies continued to spread to various parts. Although the coacervation and the continuous generation of micro-blanks greatly reduce the non-cohesion or free vacancies in the crystal when it continues to cool, and when it continues to cool, it reaches the second level of critical supersaturation, in which free vacancies in the crystal interact with oxygen and An oxygen deposition core is formed. For non-nitrogen and carbon doped crystals, the second level of critical supersaturation occurs when the crystals are cooled to about seven hundred degrees Celsius. In the nitrogen / carbon-doped stone evening crystal, the gaps formed during the load-reduction period are slightly suppressed due to the slowing of the vacancy diffusion rate. This results in a higher concentration of vacancies remaining in the crystal after the first agglomeration. The increased free vacancy concentration in the nitrogen / carbon-doped silicon also increases the temperature at which crystal supersaturation occurs at the second level, for example, at about 8 degrees Celsius to about -5050 degrees Celsius. At this increased temperature, the oxygen is more active, and more oxygen atoms and free '' T T /, said the role of the field site to make the oxygen deposition core tends to be more rampant. The stable oxygen deposition core can further retard the decomposition during the subsequent heat treatment, such as the formation of an epitaxial silicon layer. According to the present invention, the stability of the oxygen concentration core doped with nitrogen / carbon can also be incorporated into the insulator to produce a cut by implanting ions into the human body. The ion implantation has an intrinsic absorption capacity instead of being proposed on June 22 The Thermal Stability Act disclosed in US Application No. 60 / 300'2 () 8 'or incorporated with it is hereby incorporated by reference. According to the present invention, the stability of the core of oxygen concentration doped with nitrogen / carbon can also be incorporated into 6,236, U.S. Patent & Law & the method of producing stone eves on insulators -20- (16) (16) 200305932

It is hereby recorded for reference. The measurement of lattice vacancies in single crystal silicon can be performed by platinum diffusion analysis. Generally speaking, at the diffusion time and temperature selected by Yunyi, platinum was deposited on the sample and diffused on the horizontal surface, so that the Frank-Turnbull mechanism dominated the diffusion, but it fully achieved the stability of the vacancy decorated by platinum diffusion. status. For wafers with the typical vacancy concentration of the present invention, diffusion at 730 degrees Celsius and 20 minutes can be taken. At lower temperatures, such as about 680 degrees Celsius, a more accurate track can be obtained. . In addition, to minimize the possible effects of the silicidation process, the platinum deposition method is preferably less than the surface concentration of a single layer. Platinum diffusion technology has also been explained in other works, for example: Jacob et al., J. Appl. Phvs., Vol. 82, p. 182 (1997); J. Electrochemical Society, Vol. 139, p. 256 (1992), Zimmermann and Ryssel: "Diffusion of Melt Dissolve in Shi Xi under Uneven Distribution; Journal of Crystal Growth, Vol. 129, p. 582 (1993), Zimmermann, Goesele, Seilenthal and Eichiner, etc." Vacancy Concentration of Silicon Wafer Mapping ''; Appl. Phvs. Lett, Vol. 60, p. 3250 (1992), Zimmermann and Falster, π Study on the Nucleation of Oxygen Sediments in the Initial Stages of the Cekrauski Stone; π; and Appl. Phvs. A. Vol. 55, p. 121 (1992), works by Zimmermann and Ryssel, etc. Brief description of the drawings Figure 1 is a simplified diagram of the method of the present invention. -21-

Claims (1)

200305932 Patent application scope 1. Two types of single crystal wafers with two main and approximately parallel surfaces, where-the surface is the front surface of the wafer and the other-the rear surface of the wafer, between the front and back surfaces There is-the central plane,-the peripheral edge combines the front and rear surfaces, the surface layer includes a wafer region between the front surface and a distance (D) of at least about ten microns measured from the front surface to the central plane, and the body layer includes the central plane The second region of the wafer, the wafer is characterized in that: the side wafer has an uneven distribution of nucleation centers of oxygen deposits, and the concentration of the nucleation centers of oxygen deposits in the main layer is greater than that of the nucleation centers of oxygen deposits in the surface layer The concentration of the oxygen deposition nucleation center has a concentration curve, in which the peak density of the oxygen deposition nucleation center is at or near the central plane, the concentration decreases from the peak density position along the front surface of the wafer, and the wafer contains a selected Dopants of nitrogen, carbon, and mixtures thereof. When nitrogen dopants are used, the concentration of nitrogen is between about 1 × 1012 atoms and about 5 × ΐ〇ΐ4 atoms per cubic centimeter. Per cubic approximately between an outer well ⑻1 2 3 4 5 6 7 8 and about 4χΐ〇ΐ7 atoms. 1 _ As for the wafer of item 1 of the scope of patent application, the roll of nitrogen is about 1 × 10 12 atoms to about 1 × 10u atoms per cubic centimeter. 3 3. If the oldest wafer in the scope of patent application, 0 is at least about 20 microns. 4 4. If the oldest wafer in the scope of patent application, 0 is at least about% microns. 5 5. If you apply for a wafer of “Monthly Patent Offense”, d is between about% and about 6 meters. 7 6. If you apply for the oldest wafer in the patent scope, the wafer still contains crystals. An epitaxial epitaxial layer on a round surface 8. 200305932 [mmmf 7.-A method for preparing single crystal silicon wafers with controlled oxygen deposition, this method includes ... The wafer cut by the single crystal material and containing a front plane: and a central plane between the rear surface and the front and rear surfaces. This wafer includes two surface layers, a main body layer and a dopant, and the front surface layer includes a front surface distinguishing surface. The distance between the measured plane (D) to the center plane of the wafer and the two 'body layer includes the wafer area between the center plane and the front surface layer, and from the group containing nitrogen and carbon, when the dopant is nitrogen , The nitrogen desert mother cubic cm lxl012 atoms to about the field " atoms, and if you change the impurity: 丨 "carbon desert degree is about 1x1016 to about cubic meters-the original heating of the wafer at least ; t ϊίϊ: 舻 "Celsius, M degrees, to form lattice vacancies in the front surface layer and the main layer; r = t Wafer is cooled at a rate to form the concentration of vacancies in the wafer: line graph, the peak density of vacancies is in the main body layer, and the concentration is roughly decreased from the front surface direction of the peak shield wafer, and the front surface layer and the main body 2 ^ The difference in the vacancy concentration caused no oxygen deposit II to form in the front surface layer, and an oxygen deposit nucleation center was formed in the host layer; Medium two crystals = medium, which forms a stable oxygen deposit nucleation * site in the host layer The concentration of the nucleation center of the fixed oxygen sediment mainly depends on the concentration of the second place. 8 · " The method of the seventh item in the patent scope, which is above 1, Π5 degrees. For example, the method of applying for the scope of the patent No. 7 'in which the wafer is heated to about Celsius 200305932 Application # Patent light solid continuation page 1; 2, 1,200 degrees or more. 10. According to the method of the scope of the patent applying No. 7 in which the wafer is heated To about 1,200 degrees Celsius and about UK degrees. 11. The method according to item 7 of the scope of patent application, wherein the wafer is exposed to an atmospheric environment when heated, and this environment contains a material selected from the group consisting of argon, helium, neon, carbon dioxide and One or more of nitrogen or nitrogen-containing gas Groups of gases. 12. If the method in the scope of patent application No. 11 where the atmospheric environment contains argon. 13. If the method in the scope of patent application No. 丨 丨, where the atmospheric environment contains nitrogen or nitrogen-containing gas. 14. Such as The method according to the scope of the patent application, wherein the atmospheric environment contains argon and nitrogen or a gas containing nitrogen. 15. The method according to the scope of the patent application, wherein the atmospheric environment contains an oxygen partial pressure not greater than about 0.01 atmospheres 16. The method according to item 丨 丨 of the scope of patent application, wherein the atmospheric environment contains an oxygen partial pressure of not more than about 0.005 atm. 17_ The method according to item 丨 丨 of the scope of patent application, wherein the atmospheric environment contains no more than approximately Partial oxygen pressure of 0.002 atm. 18. The method according to claim 11 in which the atmospheric environment contains an oxygen partial pressure of not more than about 0.001 atmospheres. 19. The method according to item 11 of the application, wherein the partial pressure of oxygen contained in the atmospheric environment is between about 0.0001 and about 0.01 atmospheres. 20. The method according to claim 11 in which the partial pressure of oxygen contained in the atmospheric environment is between about 0.0002 and about 0.001 atmospheres. 21. The method according to item 7 of the scope of patent application, wherein the wafer is heated to at least 200305932 L ------------------- about 1,50 degrees Celsius is in the right sense Before XM forms crystal vacancies in the surface layer and the main layer, the wafer is taught to add 5 small π from ± ... to about 700 degrees Celsius to form a surface oxide fragment, which can be referred to as the day Radiator in vacancy. 22. If applying for a patent, the method around item 7, wherein the wafer is cooled at a rate of at least about 5 degrees Celsius per second in the lattice vacancies within a range of degrees of movement. 23. If applying for a patent, Shi Xizhong's relative movement is 20 degrees. The method around item 7, wherein the wafer is cooled at a rate of at least about one second within the vacancy of the crystallite. 24. Such as the patent application Fan Shi Xizhong, the relative movement is 50 degrees. The method around item 7, wherein the cooling rate of the wafer in the temperature range of the lattice space 4 is at least about per second, and the rate of the wafers in the lattice space is at least about 1 second. 25. If the method in the scope of patent application No. 7 is applied, the cold part in the temperature range of Shi Xizhong's relative movement is 100 degrees. ′ Contains stable oxygen in the main layer. It is deposited on one surface of the wafer. 26. The method according to item 7 of the patent application. After the nucleation center of the deposit has been formed, an epitaxial epitaxial layer is deposited.