TW554095B - Semi-insulating silicon carbide without vanadium domination - Google Patents

Abstract

A semi-insulating bulk single crystal of silicon carbide is disclosed that has a resistivity of at least 5000 OMEGA-cm at room temperature and a concentration of trapping elements that create states at least 700 meV from the valence or conduction band that is below the amounts that will affect the resistivity of the crystal, preferably below detectable levels. A method of forming the crystal is also disclosed, along with some resulting devices that take advantage of the microwave frequency capabilities of devices formed using substrates according to the invention.

Description

554095 V. Description of the invention (1) Scope of the invention This case is a continuation of the serial number 09 / 757,950 filed on January 10, 2001. The serial number 09 / 757,950 was filed on May 18, 1999. Continuation of serial number 0218 / 13,802 of 6,218,680. This invention relates to the growth of high-quality silicon carbide crystals for specific applications, and in particular to the manufacture of high-quality semi-insulating silicon carbide substrates for use in microwave devices. The present invention is carried out under the Department of the Air Force's agreement number F336 15- 95-C-5426. The government may have certain rights in the invention. BACKGROUND OF THE INVENTION The term "microwave" refers to electromagnetic energy having a frequency in the range of about 0 "gigahertz (GHz) to 1,000 GHz, and its relative wavelength is from about 300 cm to about 0.3 mm. Although ordinary people may most commonly use "microwaves" and cooking devices extensively, they are familiar with electronic equipment. People who know electronic equipment know that microwave frequencies are used in a wide variety of electronic applications and related electronic devices, including various communication devices, and related Circuit elements and the circuits that operate them. As is the case with many other semiconductor electronic devices and the circuits they produce, the ability of a device (or circuit) to set desired or required performance characteristics is to a great extent, and it depends on the material from which it is made. A suitable device for a microwave device = material is carbonized carbide. It provides a relatively high electrical damage field for microwave applications. This feature allows devices such as metal semiconductor field effect transistors = ET) to be used in comparison with broken gallium. The field effect transistor formed in (GaAs) operates at ten times the drain voltage. In addition, the thermal conductivity of carbonized stone is 4.9 watts per degree of hunger temperature per centimeter of paper rule ^ ^ national standard ^ • 4-554095 A7 __________ B7 1. Description of the invention (2 " ") ~ — (W / K-cm), which is 3.3 times higher than silicon and ten times higher than gallium arsenide or sapphire. These properties give silicon carbide a high power density measured in watts per millimeter (w / mm), around the gate, and an extremely high power handling capability (W / mm) in terms of grain area. This is particularly advantageous for high-power, high-frequency applications where the grain size becomes limited by the wavelength. Therefore, due to the superior thermal and electronic properties of silicon carbide at any given frequency, the silicon carbide MESFET should have at least five times the power of a device made of gallium arsenide. As anyone familiar with microwave installations knows, conductive substrates tend to cause significant problems at microwave frequencies, and they often require high-resistivity ("semi-insulating") substrates for coupling purposes. For most purposes, the terms "high-resistivity" and "semi-insulated" as used herein can be considered synonymous. In general, both terms describe semiconductor materials having a resistivity greater than about 15,000 ohm-cm (Ω-cm). This type of microwave device is particularly important for monolithic microwave integrated circuits (MMICs) that are widely used in communication devices such as pagers and mobile cleaning towels and that generally require a high resistivity substrate. Therefore, microwave device substrates are expected to have the following characteristics: · High crystal quality suitable for highly complex, high-performance circuit components, good thermal conductivity, good electrical insulation between the device and the substrate, low resistive loss characteristics, and low crosstalk. (Cross_ialk) characteristics, and large wafer diameter. … Since silicon carbide has a wide band gap (3.2 electron volts (eV) in 4H silicon carbide at 300K), this semi-insulating property should theoretically be achieved. As a result, Shida ’s resistivity silicon carbide substrate will have both power and passive devices on the same integrated circuit ("chip"), thus reducing the device size.

5. Description of the invention (3). Silicon carbide can also provide other properties that have no physical, chemical, or electrical properties, and improve its efficiency and performance, including the ability to operate at high temperatures and destroy. ‘Second: As known to those of L Carbide, the anti-fossil runes formed by most technologies are generally too conductive for these purposes. Youpen, the nominal or accidental nitrogen concentration in the carbides has a tendency to be sufficiently high in the sublimated growth crystals (1_2xloI7 / cm3) 'and will provide sufficient conductivity to prevent such carbides from being used in microwave devices. Sex. In order to be particularly useful, a carbonized carbide device should have a substrate resistivity of at least 1500 ohm-cm (Ω_㈣) to achieve dynamic behavior. In addition, it is necessary to measure the resistivity of ohm_cm or more to minimize the transmission line loss of the device to 01 decibels 公) / cm. In order to insulate the device and minimize the backgating effect, the resistivity library of semi-insulating carbides is close to the range of 50 ohms or more. The current research work tends to advocate that the semi-insulating behavior of the carbide base material is a result of the deep energy levels within the energy band gap of the carbide body; that is, it is farther away from the energy levels generated by the p-type and erbium dopants. In the valence band and conductive band: example. ’U.S. Patent No. 5,6ιι, 955. According to the 955 patent, the deep energy levels of the carbides between the valence band and the conductive band can be brought to carbon by controlling the combination of selected elements such as transition metals or chalcogens such as hydrogen, gas, or H. Fossil Xizhong 'is generated by the formation of deep energy level centers in carbonized fossils; for example, row 3, line π ". Also comes to' Mitchel '4H-SiC. I" in SIMC_X "electron volt deep energy level ^ u eV Deep Level in 4H_Sic.SIMC_x), Berkeley, California, i99_ June; Hobgood, semi-insulating QH_sic 554095 A7 B7 grown using physical vapor transport V. Description of the invention (4) (Semi-Insulating GH-SiC Grown by Physical Vapor Transport), Appl. Phys. Lett., Vol. 66, No. 11 (1995); W〇95 / 04171; Sriram, RF Performance of SiC MESFETs on High Resistivity Substrates), IEEE Electron Device Letters, Volume 15, No. 11 (1994); Evwaraye, Examination of Electrical and Optical Properties of Vanadium in Bulk n- type Silic on Carbide), J. Appl. Phys. 76 (10) (1994); Schneider, Infrared Spectra and Electron Spin Resonance of Vanadium Deep Level Impurities in Silicon Carbide), Appl. Phys · Let · 56 (12) (1990); and Allen, Frequency and Power Performance of Microwave SiC FET's, International Conference on Silicon Carbide and Related Materials (Proceedings of International Conference on Silicon Carbide and Related Materials) 1995, Institute of Physics

Physics) o In addition to conventional ideas, these deep-level elemental impurities (also known as deep-level trapping elements) can be grown by high-temperature sublimation or chemical vapor deposition (CVD) of high-purity silicon carbide. Introduced and added. In particular, vanadium is considered a desirable transition metal for this purpose. According to the 955 patent and similar technologies, vanadium compensates silicon carbide materials and produces the high resistivity (ie, semi-insulating) properties of silicon carbide. However, the introduction of vanadium as a compensating element to produce semi-insulating silicon carbide will also bring the paper size to the Chinese National Standard (CNS) A4 specification (210X297 mm) 554095 5. Description of the invention (5 ,,: Disadvantages., Baixian ' In the presence of any dopant with a significant amount of electrons, Renji 9 has a negative impact on the crystalline quality of the resulting material. Therefore, reducing or eliminating Zhiqigan can increase the crystal quality of the resulting material to a significant degree and element. The quality of the child. In particular, the current understanding is that the compensation of starvation has caused the growth of carbon nanotubes (micropipes) 0 μm. 4 The second disadvantage is that the introduction of compensation vanadium will reduce the margin of silicon carbide. The manufacturing cost of materials. Wang Yi ν means strength + absolute clothing. In the second place, the active compensation of slave silicon or any other half ::: may be said to be slightly complicated and unpredictable, so :: to create complexity Therefore, if supplementation can be avoided, it can be avoided as scheduled in the patent filed on May 18, 1999, and in ㈣ 2 〇 9 / 757,95G, which was filed on _w10, and disclosed- An improved semi-insulating carbon cut, where Carbon compensation: In silicon single crystals, the concentration of vanadium is maintained below a detectable (e.g., SIM: ·: loose test) value. When explaining the related doping, the 802 application and many prior art techniques sometimes sometimes A specific dopant is referred to as "deep" < "shallow". Although the terms "deep" and "夂" may have descriptive values when describing the states and energy levels associated with a particular dopant You can get the best understanding of the relative taste, not the limit. U In each case, the energy level above 300 millielectron volts from the edge of the band is called "deep". However, ... Some 7L elements (for example, boron) that have energy levels in this range can also act in a "shallow" manner; that is, they can produce conductive energy levels rather than energy levels that increase resistivity. In addition, like boron (b) 's情 -8- This paper size is applicable to the GG standard (CNS) M specification (2lGX297 public love) 554095 A7 _________ B7 V. Description of the invention (6) In the case, individual elements can generate more than one energy level in the energy band gap Therefore, it is an object of the present invention to provide a method which is not generally defined as "deep" or " "Semi-insulating silicon carbide substrate with specific dopants, and a semi-insulating silicon carbide substrate with the necessary and beneficial capabilities for high-frequency operation, but at the same time avoiding the disadvantages of previous materials and technologies. The present invention This object is achieved by a semi-insulating bulk single crystal of silicon carbide having a resistivity of at least 5000 ohm-cm at room temperature and a transition element concentration lower than 1E16. Another aspect of the present invention is an Silicon carbide with a resistivity of at least 5000 ohm-cm at room temperature, and a capture element concentration that produces a valence energy or conductive band of at least 700 millielectron volts, which is lower than the amount that affects the electrical characteristics of the crystal The semi-insulating bulk single crystal. Yet another aspect of the invention includes a device incorporating a semi-insulating silicon carbide according to the patented invention, which includes a MESFET, a specific MOSFET, and a HEMT (High Electron Mobility Transistor). The foregoing and other objects and advantages of the present invention and the manner of accomplishing the same will be more clear based on the following detailed description in conjunction with the accompanying drawings, in which: Weekly brief description Figures 1 to 3 are performed on a wafer manufactured according to the present invention Fig. 4 is a graph of the effect measurement; Fig. 4 is a graph of the natural logarithm of the carrier concentration of the semi-insulating silicon carbide according to the present invention versus the temperature (Kelvin temperature); Fig. 5 is a semi-insulating carbonization according to the present invention The natural logarithm of the resistivity of silicon is -9- 554095 A7 B7 V. Description of the invention (7 Graph of temperature reciprocal; Figures 6 to 8 are the same measurements as shown in Figures 1 to 3, but taken from different substrate wafers Figure 9 is another graph illustrating the natural logarithm of the carrier concentration in the samples of Figures 6 to 8 versus the reciprocal temperature; Figure 10 is again about the natural logarithm of the conductivity measured in the samples of Figures 6 to 8 versus the reciprocal of temperature Another figure; Figures 11 to 13 are still another set of figures similar to Figures 1 to 3 and 6 to 8 regarding yet another measurement on different parts of the semi-conductive silicon carbide material; Figure 14 is illustrated in Figure Natural logarithm of resistivity versus temperature for samples from 11 to 13 Another figure of the countdown; and Figures 15, 16, and π are diagrams of the second ion mass spectrometry (SIMS) of various samples of materials according to the present invention and prior art materials. Detailed description in the first embodiment The present invention is a silicon carbide having a transition element concentration lower than that of the element dominating the crystal resistivity, and a silicon carbide which is better at a concentration lower than 10 · 丨 6 per cubic centimeter (cm · 3) (ie, 1E16). It is a semi-insulating single crystal. In another specific embodiment, the present invention has a resistivity of at least ohm-cm at room temperature, and has more electrical characteristics that will affect the crystal: Semi-insulating bulk single crystal of silicon carbide that captures elemental concentration in a state of a conductive band of at least 700 millielectron volts. The term "transition element" when used in carbides here means the value when formed on silicon carbide. The energy level between the energy and the conductivity added by the dopant to the band is -10-

554095 A7 --------- B7 V. Description of the invention (8) More conventional p-type or n-type dopants are farther away from the elements of the periodic table in the state of conduction and valence band. As described in the field and background, vanadium is a common transition element with such characteristics. As used further herein, a concentration defined as "below detectable value" refers to an element that exists in an amount that cannot be detected by new sophisticated analysis techniques. In particular, since a more commonly used technique for detecting small amounts of elements is second ion mass spectrometry ("SIMS"), the detectable limit referred to herein is below 1/10, cubic centimeters (1). 16), or in other cases, amounts of elements such as vanadium and other transition metals present in an amount below about 1E14. These two quantities represent typical detection limits for most trace elements (especially vanadium) using SIMS technology; for example, SIMS Theory-Sensitivity and Detection Limits ^ Charles

Evans & Associates (1995). As mentioned earlier, vanadium (V) is a more commonly used element for the manufacture of semi-insulating silicon carbide. Because of this, the present invention is characterized by the absence of ^, or, if it exists, it is present in an amount that is substantially lower than the resistivity that substantially affects the crystal, and in an amount that is preferably less than 1E 16. -Although there may be other polytype structures (ie, crystal structures), the silicon carbide single crystal according to this embodiment of the present invention has a structure selected from the group consisting of%, 4Η, 6H, and 15R polytype structures. The multi-type structure of the group is better. ... to avoid the problems associated with the presence of nitrogen and the need to try to compensate for the nitrogen 'according to this specific embodiment of the present invention, the carbonized stone is described as having a content of less than about 1 x 7 / cm3 (iei7) The nitrogen atom concentration is better: B. The silicon carbide semi-insulating single crystal according to the present invention has a nitrogen concentration below 5E16, which will be -11-554095 A7 B7 5. The invention description (9) is better. The concentration of Syria is below 1E16 atoms per cubic centimeter, and below 1 £ 14 atoms per cubic centimeter is the best. In addition, the resulting monolithic carbide carbide evening crystals will have a resistivity of at least 10,000 ohm-cm at room temperature, and a resistivity of at least 50,000 ohm-cm at room temperature will be the best. To provide a semi-insulating silicon carbide substrate for high-frequency MESFETs, the 4Η? Type surname is preferred due to its higher overall electron mobility. For other ° devices, another multi-type structure may be better. Therefore, one of the more preferred embodiments of the present invention has a resistivity of at least 10,000,00 ohm · cm at room temperature ^ a half-I edge block of carbonized fossil with a Ka atom concentration lower than the old 4 Crystalline single crystal. The method for manufacturing the semi-insulating bulk single crystal of carbonized carbide powder includes heating the carbonized powder powder to sublimation, while heating the carbonized powder powder, and then maintaining the temperature of the source powder at a low temperature: At this temperature, it is better that the sublimated species of the Wuyuan powder will condense on the seed crystal. Thereafter, the & method includes continuing to heat the silicon carbide source powder until a desired amount of single crystal overall growth occurs on the seed crystal. The characteristics of this method are: 0) the amount of the transition element in the source powder (as described above) is lower than the relevant amount, (2) the source powder contains ^ 'below MM and (3) the sublimation grows in the spear.胄 source powder and seed crystals are maintained at two enough, and can significantly reduce the amount of lice in whole limb growth that can be added to the seed crystals in other cases, and the overall growth of seed crystals The number of spot defects (sometimes called intrinsic spot defects) is increased to the respective temperatures of the amount of the resulting carbide-like early crystals that become semi-insulating. The preferred way and conceptually 'by keeping the amount of nitrogen or other dopants as low as possible, the number of dot defects required to make the crystal semi-insulating is also minimized. Item paper 554095 Five invention descriptions (10 before '· = γ The preferred number seems to be in the range of 1E15_5E17. Two are the semi-insulating silicon carbide according to the present invention, the source powder used must be 3 vanadium Or if vanadium is present, it must be lower than the detectable value. As before _ privately measured values are typically set to values that can be measured using SIMS. The amount of vanadium in the source meal for σ is less than 1E16 atoms Per cubic centimeter is better, and less than 1E14 atoms per cubic centimeter is best. In the preferred embodiment, by using high purity graphite as one of the raw materials of W, and by using purified graphite parts in the reactor itself ' Minimize lice. In general, graphite (in terms of source powder or reactor parts) can be heated by heating in the presence of a pheromone gas (eg, in the presence of) and, if necessary, in an inert atmosphere (eg, Ar). It is further heated ("bake out") at about 2500 ° C to purify possible doping elements such as boron or aluminum. Appropriate purification techniques are also known in the art (for example, U.S. Patent No. 5,336,520, 5,5〇5,9 29, and 5, 7G5, 139, and if necessary, can be implemented without much experimentation). According to the present invention, it has been found that the amount of nitrogen in the formation of bulk single crystals can not only be obtained by using in the prior art ^ And the purity technology (which is naturally recognized as part of the technology of the present invention), and can be sublimated at a relatively high temperature, while maintaining the temperature of the seed crystal and any overall growth on the seed crystal low It is lowered at the temperature of the source powder. A better technique for sublimation growth (except for the modification as described here) is described in US Patent No. 34,861, the content of which is fully incorporated herein by reference. Medium ("the '861 patent"). Sublimation is performed in a suitable crucible, as described in the 86 1 patent, 554095 A7 ----------- B7 V. Description of the invention (~ --- It is typically made of graphite. ⑽a, 々 is used to form a crucible that includes seed fixtures, and all of them are set inside the sublimation furnace. Tab + surface ^ Now select and purify the Sic source powder to have less than Nitrogen concentrations 痄 η, ^ of about 1E 1 7 and less than about 5 Ε 16 is preferred. Furthermore, the source powder has a green dot may affect more heteroatoms seventy-two ^ s, a low amount of the electrical characteristics of the body of the vanadium or other heavy metals or transition elements of the spread of said said ^. Such an amount comprising less than sims The amount of measurable value, which is at least less than ιΕ 心 6, and lower than that of Baxinming's SIMs. The source powder satisfies the other advantages described in the 86 1 patent. The characteristics are also better. When Tian Lijin boron is used as the acceptor, it is best to add it in the form of a source material (powder) that includes the desired amount. From the perspective of Beiji, the sublimation of carbonized rocks can be used at will. The source temperature is from 0 to about 2500 ° C, and the temperature of the seed crystal is kept proportionally low. Regarding the materials described herein, the sources are maintained at approximately 236.0 and 238. 〇 = In between, the seed was maintained at 300 · 35 × χ ^ τ. As known to those familiar with such procedures and measurements, the temperature indicated may depend on how and where the system is measured, and there may be slight differences between different systems. Since the vanadium series has previously been selected as a selective element for compensating semi-insulating silicon carbide, the present invention can be expressed as a bulk SiC single crystal in which the vanadium series is lower than the detectable and numerical values quoted above and its manufacturing method. However, those familiar with the growth of silicon carbide and the characteristics of silicon carbide used in semiconductor applications will understand that the present invention also considers that there are no other elements that would have the same functional characteristics (and potential disadvantages) as vanadium. By avoiding the use of such elements, the present invention also eliminates the need to compensate for this element with other elements, and correspondingly reduces this compensation for crystal growth. -14- This paper size applies Chinese National Standard (CNS) A4 specifications (210 X 297 mm) 554095 A7

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Destiny 554095 V. Description of the invention This image can be used ^; ^ Sophie ☆ Gu Shiren The exclamation and this figure are used to determine the activation energy of the 4-inch activation gate of semi-insulating silicon carbide material. In other words, the live moon dagger S and the difference measured in Figures 4 and 5 are within the expected experimental limits, and the data can confirm each other. Figures 6 to 10 are the same types of measurements and maps as Figures 1-5. However, they are taken from different samples; specifically, they are different regions of the same wafer as measured in FIGS. Therefore, it can be seen that Figs. 6 to 8 are consistent with the results depicted in Figs. More specifically, Fig. 9 (which is another graph of the natural logarithm of the carrier concentration versus the reciprocal of temperature) shows the calculated activation energy of ⑻-227 electron volts. Similarly, this is within the experimental limit of U electron volts measured earlier. Figure 10 depicts the natural logarithm of resistivity versus temperature inverse in a similar manner, and it also provides an activation energy of 1.01159, which is also at U Within the experimental limits of electron volts. Figures 丨 to 13 show results from another part of the wafer 'but they are considered to be less favorable than the results seen in previous measurements. In particular, the graph of FIG. 11 cannot form a straight line in a desired manner, and the data is less favorable than the previous results. Similarly, Figure 14 depicting the natural logarithm of resistivity versus the reciprocal of temperature shows only a calculated activation energy of 0.629399, a value that deviates greatly from 1 丨 electron volts and has nothing to do with experimental unreliability. Figures 15, 16, and 17 present second ion mass spectra (SIMS) of various comparative samples, and they tend to show elemental impurities and other materials in semi-insulating silicon carbide substrates. Fig. 15 is a SIM S spectrum of a semi-insulating carbide fossil material according to the present invention, and it is confirmed that there is no starvation or any other problem in the sample.

V. Explanation of the invention (14) The activation energy and intermediate energy gap state of the present invention in the present invention is not generated by the presence of vanadium or other transition metals. Fig. 16 is for comparison 'and it is neither a semi-insulating nor a silicon carbide manufactured according to the present invention, but a SIMS spectrum of a 沭 -type wafer showing a conductive silicon carbide sample. The reason for the absence of N-type substrates including thorium is that vanadium is absent from the amount spectrum. 'Figure 17 provides a comparison of the previous version of semi-insulated carbonized hair with compensated gadolinium. The chirped peak appears strongly at about 51 atomic mass units in the spectrum. This vanadium wave is clearly absent in Figures 15 and 16. : Of course, those familiar with these materials should understand that although the phrase "below the detectable amount" is a completely appropriate description of the present invention, it can also be understood to be equivalent to less than the electronic characteristics that will affect the carbonized broken crystals, And especially the resistivity. Therefore, another aspect of the present invention includes a semi-insulating carbon cut single crystal with a donor dopant, an acceptor dopant, and a timely defect. In this aspect of the present invention, 'the number of donor dopants in the silicon carbide crystal is greater than the number of body dopants (Na)' and the number of intrinsic dot defects in the carbides as the acceptor ( Nd |) is larger than the numerical difference between the number of these donor and acceptor dopants. Regarding this aspect, the concentrated production of transition elements and heavy metals is lower than the concentration that will affect the electrical properties of the carbide single crystal, and it is better than the second best. The resulting silicon carbide single crystal has a resistivity of at least 5,000 ohm-cm at room temperature, preferably at least 10,000 ohm-cm, and most preferably 50,000. This aspect of the invention is also applicable to the number of acceptor dopant atoms compared to the donor 554095 A7

The number of dopant atoms with complementary dots has a larger number of inherent point defects than the number of donors. condition. In this case, F & in the clear state, 'as the donor atom and the number of impure impurities or another impure agent atom, in other words, the shallow η-type and ρ-type dopants compensate each other, where One dominates to a certain degree. The number of solid particles in the electro-activated crystal is larger than the net amount of n-type or p-type doping that is dominant in the crystal over the other. Described by equations,

Ndi > (Nd ~ Na) where the donor has an advantage over the acceptor, or

Ndl > (Na — Nd) Doped body point spot defects. The acceptor is more dominant than the donor. In the first case, the crystal compensates for the n-type dominated by agent atoms. However, these net donors were once again compensated for by defects, resulting in semi-insulating crystals. In the second case, it acts as a donor and compensates for the net excess of acceptors in the crystal. As used herein, the term "dopant" is used in a broad sense; it is used to describe silicon removal (Si) or silicon that is present in a crystal lattice and provides additional electrons (donors) or extra holes (forks). Atoms other than carbon (0). In the present invention, a dopant may exist passively or actively; that is, the term "dopant" neither implies the "doping" step nor does it exist. In a preferred embodiment The acceptor is boron. In this specific embodiment, the boron overcompensates nitrogen and the point defect as a donor overcompensates boron, resulting in semi-insulating silicon carbide crystals. The behavior of boron as an acceptor is contrary to previous concepts, Among them, boron is regarded as a deep capture element (for example, commonly assigned US Patent No. 5,270,554, line 8 to line 49-51). In fact, the national standard (CNS ) A4 size (210 X 297 mm) 554095 V. Description of the invention (16) 700 耄 耄 electron volts in SiC,. ^ A Old capture moon dagger, but (so far) it is not reproducible . So, right, _ Jing Xizhu p visited Shan Benming and found that boron It is described here as a suitable acceptor dopant for silicon, silicon, silicon, titanium, silicon, silicon, titanium, and silicon. In this preferred embodiment, Zheng Shigan, T Stone Reversed Silica is available in Boron that reduces the concentration of active nitrogen to very little I (preferably about 1E15 5 butterfly) will make the crystal grow under the condition of ρ-type value. Through batch production 4, 4, and 乜 make long conditions, can make the point The concentration of the defect reached about 5 Ε1 5 'therefore excessively supplementing monks and coffee branches' to supplement boron, and to produce semi-insulating crystals. By reducing the qi "Chen degree" and the relative compensation shed Xi Yue. The invention can avoid the loss of previous metal transitions dominated by heavy metal and doping and compensation. Since the crystal growth of SiC is a very complicated procedure, the exact parameters can be seen locally or individually, such as within a proper range. The specific temperature used and the characteristics of the equipment used (· generated differently 'However, based on the disclosure herein, it is expected that those skilled in the art can successfully practice the present invention without undue experimentation. It is expected that the carbonized stone can be irradiated Neutrons, high-energy electrons, or gamma rays In order to generate the desired number of point defects', the number of point defects is controlled to a certain extent, and the result is consistent with the equation described above. Although it is difficult to measure the exact number of 1 point defects, such as electronic paramagnetic resonance (EPR ), Deep-level transient spectroscopy (DLTS), and position extinction spectroscopy can obtain the best available indication of the number of existences. As further described in the text, the Hall effect measurement also confirms the desired properties of the crystal. In another complaint, the present invention can be incorporated into active devices using semi-insulating silicon carbide substrates, especially active microwave devices. As previously mentioned and as known to those familiar with active semiconductor microwave devices, as opposed to when Ideally, the carrier is limited to the special channel and other functional parts of the microwave device. The standard of this paper is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 554095 A7 ______B7 V. Description of the invention 7 17) '' The frequency used to operate a microwave device is significantly hindered by any interaction between the carrier and the substrate. The properties of the silicon carbide semi-insulating material according to the present invention are such that it has excellent performance characteristics in a suitable device. These devices include, but are not limited to, MESFETs, specific MOSFETs, and other devices such as those described in the following patents: Application Nos. 5,27〇, 554, 5,686,737, 5,719,409, 5,831,288 in this US patent and application No .; Serial No. 08/891, 221 filed on July 10, 1997; and Serial No. 09/082, 5 54 filed on May 21, 1998; the titles of the two articles are "Punching Free Power 11] ^ 〇 3 Latch-up Free Power UMOS Bipolar Transistor "; Structure No. 08 / 797,536 filed on February 7, 1997, r Structure for Increasing the Maximum Voltage of Silicon Carbide Power Transistors "; Application Serial No. 08 / 795,135 dated February 7, 1997," Structure to Reduce the On-resistance of Power Dransistors "; and 1998 International Application No. 0 丁 / 1 ^ 98/13003 (designated US) filed on June 23, 2010, "Power Devices in Wide Bandgap Semiconductors" , The entire contents of which are incorporated herein by reference. Experiments In the Air Force Research Laboratory (Dayton, Ohio) (Wright-Patterson Air Force Base), the high-temperature Hall effect and SIMS were used to detect two wafers of semi-insulating SiC. It is not possible to obtain intelligible results from one of the wafers (possibly due to unsatisfactory ohmic contact), but two Halls-20 from the second wafer-This paper size applies Chinese National Standards (CNS) A4 size (210X297 mm) 554095

The samples all produced the same results, and reasonable viability was obtained from these results. Both wafers are insulated at room temperature. Estimating the θ and G margins enables thermal activation of measurable wafers at high temperatures, and measurement of carrier carrier degrees. Due to the low mobility involved in ancient, Japanese, and Arabesque dishes, this is not always possible in semi-insulating materials. " Alas. The carrier "Chen degree" is about 10 5 / cm 3 at 1000K, of which the resistance umbrella is privately recognized, ΔI and sheep are about 103 ohm-cm. The concentration of this kind of carrier is about one to two orders of magnitude lower than that of the conventional semi-insulating material. Bran-^ ..., Lijiu However, it is not possible to perform a regression of the η vs. 1 / T curve ', so the total concentration of active a and green and curved injection layers cannot be obtained. The activation energy is about 1.1 electron volts. 0 Using the south resolution system, the sample is pushed up and qta is used to order the SIMS. Except for some copper and some hydrogen which are close to the detection limit, and other materials were detected by Wei Herui, it is estimated from the height of the mass 47 wave peak. Therefore, due to the fact that Ding u 47, the peak system of B 47 is attributed to

SiOH. The scans of the properties of the present invention, y I, / η π, a & M and Y, and the two comparative samples are included in Figures 18-20, respectively. In Figs. 19 and 20, titanium (Ti) is apparently at about χ 10/10 / cm3, but it does not appear in the sample of the present invention (Fig. 18). Vanadium also appears in standard semi-insulating samples along with SiOH lines indicating hydrogen. . 〇 (Figure 20). From these results, the '-wafer is considered to be a very high-purity material, and since any remaining vanadium impurities are present along with other defects that make up the U-electron volt energy level, the concentration of the shallower impurities is greater, and therefore The electron volt level compensates for shallow impurities, so it is considered to be insulating. The fermion m therefore makes the material ^ insulating. The presence of hydrogen may mean that hydrogen compensation occurs, but it is expected that it will selectively compensate or neutralize the shallower impurities and not the deeper energy levels. 〃 Staple f -21-

554095 A7 B7 V. Description of the invention (19) In the drawings and description, typical specific embodiments of the present invention have been disclosed. Although specific terms are used, they are used only in a general and illustrative sense, not as For limited use, the scope of the invention is described in the following patent application scope. -22- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)

Claims (1)

5 5 Wei Fanli A BCD 1 · A semi-insulating carbonization; g evening single crystal, including: and the donor dopant and acceptor fixed in the carbonized stone evening single crystal are a bit defective; of which-the first conductivity type doping The number of dopants is greater than the number of dopants of the first type; and > tf is the number of inherent point defects in the carbonized carbide crystal of the first type of dopant used to compensate for dominance compared to the first type. The dopant has a large difference in the value of the super-type dopant; and the concentration of a salesman's transition element is less than 1E16; the carbon-cut single crystal has at least 5 () ⑽ohm_cm at room temperature. i 2.-A kind of carbon-cut semi-insulating bulk single crystal, which has a resistivity of 1 to 5 at room temperature, and a resistivity of 5 ohm-cm, and has a lower generation energy than the amount that will affect the duality of the crystal. Or the concentration of the capture element in the conductive band of at least 7000 millielectrons. Note 3. Carbonized 1X1 according to item 丨 or 2 of the scope of patent application. The gas atomic concentration of "/ cm3." "Earthly, it has a carbon-cut single crystal that is less than 4. f according to the patent claims, or 2 items, in which the degree is less than 1 X 1016 / cm3. Chen 5. According to the semi-insulating carbon carbide crystal of item i in the scope of the patent application, the first type dopant is the donor, the second type dopant is the acceptor X, and the inherent point defect is used as the acceptor. body. 6. According to the patent, the semi-insulating carbon cut crystal of item 5, the acceptor includes boron. "Yd -23- The size of this paper is General Ningguo National Standard (CNS) M specification (21GX297 public director) 554095 A8 B8 λ = semi-insulating carbon carbide crystal of item 1 of the scope of patent application, wherein the first type of dopant is the acceptor, the second type of dopant is the donor 'and the intrinsic point defect is the donor. 8. The broken single crystal of carbide according to item 1 or 2 of the patent application, wherein the polytype structure of the silicon carbide is selected from the group consisting of 3C, 4H, 6H, and 15R polytype structures. 9. According to the scope of the patent application, item 1 or 2 of the carbonized eve single crystal, wherein the nitrogen concentration is 5 X 106 or less per cubic centimeter. 10. The silicon carbide single crystal according to item 1 or 2 of the patent application scope, wherein the vanadium concentration is lower than a value that can be detected by the second ion mass spectrometry (SIMS). U. The carbide single crystal according to item 1 or 2 of the scope of the patent application, wherein the vanadium concentration is lower than 1 × 10 4 / cm 3. 12. The silicon carbide single crystal according to item 1 or 2 of the patent application scope, which has a resistivity of at least 10,000 ohm · cm at room temperature. 13. The silicon carbide single crystal according to item 1 or 2 of the scope of the patent application, which has a resistivity of at least 50,000 ohm-cm at room temperature. 14. A transistor ' having a substrate comprising a bulk single crystal according to item 1 or 2 of the scope of the patent application. 15. The transistor according to item 14 of the scope of the patent application, which is selected from the group consisting of: metal-semiconductor field effect transistors, metal-insulator field effect transistors, and high electron mobility transistors. — _--This paper is compliant with China Standards (CNS) A4 specifications (210 X 297 public love) Binding line