JPH02217395A - Massive body of crystalline silicone nitride - Google Patents

Abstract

PURPOSE:To obtain a massive body mainly comprising beta-crystal, containing columnar TiN and orienting beta-crystal by directly generating massive body in making Ti-containing Si3N4 by chemical vapor phase deposition method. CONSTITUTION:The subject crystalline Si3N4 massive body is composed of >=50 wt.% beta-type crystal and contains columnarly separated TiN along c-axis direction of beta-type crystal and preferentially oriented (00l) plane in beta-crystal. Although hardness of said massive body is different with temperature at production, the massive body is able to be sufficiently used as cutting tool. Besides, as said massive body has high electric conductivity and small temperature coefficient of electric conductivity, application as electric material utilizing said properties is expected. Said massive body is obtained, for instance, NH3 gas is blown through inner tube 8 of combined tube 4 and mixed gas of SiCl4 and TiCl4 is blown through outer tube 9 onto a substrate heated at 1400 deg.C with respectively fixed conditions and deposited.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a crystalline silicon nitride mass produced by chemical vapor deposition.

(Prior Art and Problems to be Solved by the Invention) Conventionally, a method of manufacturing silicon nitride using a chemical vapor deposition method is known. In this case, the raw material gas used in the above method is a silicon deposition source gas containing silicon and depositing in a vapor phase, such as 5iC14°SiH, SiBr4. S
iF, etc., and nitrogen deposition source gases that contain nitrogen and precipitate in the gas phase, such as N11s and Ntlln, are used. When the two types of gases are reacted under reduced pressure and at high temperature, It is known that when silicon nitride is precipitated, for example, if a carbon plate is present, silicon nitride is deposited in the form of a plate on top of the carbon plate to obtain an amorphous or crystalline silicon nitride block.

It is also known that in addition to silicon nitride lumps, amorphous silicon nitride powder can be produced by changing the precipitation conditions.

By the way, regarding silicon nitride containing Ti, US Pat. No. 4,145,224 discloses that a powder body can be obtained using a chemical vapor deposition method.

That is, according to the same publication, by introducing StCEl rtc E 41 N113 into a reaction region of 1100 to 1350°C, an amorphous silicon nitride powder containing TiN can be obtained, and an amorphous silicon nitride powder containing no TiN can be obtained. Crystallization of powder requires a heat treatment temperature of 1500 to 1600"C, whereas amorphous silicon nitride powder containing TiN requires a heat treatment temperature of 1500 to 1600"C.
At a lower temperature of 400° C. in N2 for 2 hours, 60% by weight crystallizes, consisting of 97% by weight of α-type silicon nitride and 31% by weight of β-type silicon nitride. Note that the Ti content is preferably 1.5 to 5% by weight, but 0.
．． It is described that amorphous silicon nitride is crystallized at 1400''C even when Ti is contained in an amount of 0.1% by weight.

Furthermore, according to the above-mentioned US patent publication, Ti is precipitated and generated.
It is described that silicon nitride containing .

The present invention consists of at least 50% by weight of β-type crystals, which have not been known in the past, and includes TiN precipitated in a columnar manner along the C-axis direction of the crystals, and the β-type crystals (00ff
i) It is an object of the present invention to provide a crystalline silicon nitride block whose planes are crystal oriented.

(Means for solving problems) Next, the present invention will be explained in detail.

The present invention consists of at least 50% by weight of β-type crystals,
The present invention relates to a crystalline silicon nitride block containing TiN precipitated in a columnar manner along the C-axis direction of the crystal, and in which the β-type (002> plane is crystal oriented).

As mentioned above, silicon nitride powder bodies containing Ti that are mainly amorphous are known, and silicon nitride sintered bodies that are crystalline and contain Ti are also known, but as in the present invention, at least A crystalline silicon nitride block consisting of 50% by weight β-type crystals and containing Ti has been completely unknown.
According to U.S. Pat. No. 4,145,224, a silicon nitride powder containing amorphous Ti is obtained, and when this powder is molded and fired, a crystalline silicon nitride sintered body containing Ti is obtained. It is disclosed that this can be obtained. However, as can be seen from the above-mentioned US patent publication, this was obtained by molding and firing a powder, and was not originally a lump.
Moreover, most of the crystalline 5iCffi4 contained in the molded body, ie, 97% by weight, is α-type crystal, and the β-type crystal is in a small amount, ie, 3% by weight.

The present invention comprises at least 50% by weight of β-type crystals, includes TiN precipitated in columnar shapes along the C-axis direction of the crystals, and includes Ti in which the (001) plane of the β-type crystals is oriented. Si3N4 agglomerates, such agglomerates are completely new.

Next, the structure, properties, and properties of the Ti-containing 5iJn aggregate of the present invention will be explained.

The agglomerate of the present invention is composed of at least 50% by weight of β-type crystals, and Ti is precipitated in columnar shapes along the C-axis direction of the crystals.
As shown in the X-ray diffraction diagram of FIG. 1, the (002) plane of the β-type crystal is extremely well oriented, and this crystal orientation is shown in the surface scanning electron micrograph of FIG. The plate-like zero surface of type Si3N is very well matched with the stacked structure.

Ti in the agglomerates of the present invention exists as TiN. As shown in the high-resolution electron micrograph of the containing surface, TiN is precipitated as columnar inclusions of several tens of diameters and extending in the C-axis direction of β-type Si3N. The content of TiN in the agglomerate varies depending on the conditions under which the agglomerate is produced, especially the production temperature, as will be described later, and is within the range of 4 to 5% by weight.

The density of the agglomerates of the present invention varies depending on manufacturing conditions, but
．． The theoretical density of α-type Si3N is 3.18 g/cm3, that of β-type 5iJ4 is 3.19 g/cm', and that of TiN is 5.43 g/cm'. Therefore, the density increases as the TiN content increases. The hardness at room temperature (load 10 hours) of the lump of the present invention is 1900 to 2900 kg/aua.
The hardness is within the range of t, and as will be described later, this hardness varies depending on the temperature at which the lump is produced. The block of the present invention having the above-mentioned hardness can be satisfactorily used as a cutting tool.

The Ti-containing SiJ lump of the present invention is pure 5iJn
For example, as shown in Figure 4, the electrical conductivity of amorphous 5izN4 containing Ti at 300°C is higher than that of α-type Si3N not containing Ti at the same temperature.
, (2) are each seven orders of magnitude higher, and the temperature coefficient of electrical conductivity is small.

Since it has the above-mentioned electrical conductivity and a unique temperature coefficient of electrical conductivity, it is expected that it will be applied as an electrical material utilizing these properties.

Next, the manufacturing method of the present invention will be explained with reference to FIG.

According to the present invention, a nitrogen deposition source gas, a silicon deposition source gas and a titanium deposition source gas are each sprayed onto a substrate 2 heated within a temperature range of 500 to 1900'C using a combination tube 4, at which time the The periphery of the nitrogen deposition gas flux blown onto the substrate 2 is surrounded by a mixed gas of the silicon deposition source gas and the titanium deposition source gas, and the gas phase decomposition reaction of both gases is caused to occur on the substrate 2.
Si3N containing Ti generated on or near the substrate 2
, and the Si3N containing the formed Ti can be deposited as a lump on a substrate.

Note that it is advantageous that at least the tip end and the base of the combination tube are both placed in a closed container where the atmosphere and pressure can be adjusted.

As a silicon deposition source compound which is one of the starting materials for producing Si3N containing Ti in the present invention, silicon halides (
StCln, 5tp4. SiBr, 51141
S+2Cf6゜5izBrh, 5izla+ 5i
BrC1,3,5iFlr3C1, 5iBr2Cl.

5ilCf3), hydrides (SiHn, SiJ+ 0
．． 5ii) Is, 5izll, ), hydrogen halide (SiHCl 3.5iHBr3. SiHF3.5i
Any one or two or more selected from HI2) can be used, preferably S which is gaseous at room temperature.
iH, or 5iHCf with high vapor pressure at room temperature
,.

5iCffi, can be used advantageously. Also, as a nitrogen deposition source compound, a hydrogen compound of nitrogen (HN3゜N
II+, NJn), ammonium halide (Nl(
4 (l.

NH4F, NH4HF! , N1141) can be used, and NH3°NlH4 can be preferably used because it is relatively inexpensive and easily available. In addition, titanium halides (TiCr) are used as titanium deposition source compounds.
4°TiBr4. TiF4. Any one or two or more selected from Ti1a) can be used; TiCr2. Since it is relatively inexpensive and easily available, it can be suitably used.

The temperature of the substrate from which Si and N containing Ti are obtained from the silicon deposition source compound, titanium deposition source compound, and nitrogen deposition source compound is 50
Within the range of 0 to 1900°C, but 1000 to 160
It is preferred to use a temperature range of 0°C.

Note that N2 is used to transport one or both of the nitrogen deposition source compound, silicon deposition source compound, and titanium deposition source compound.
．． One or more of ^r, He, and It□ can be used as a carrier gas, if necessary. Of these, N2 can also be a source material for nitrogen deposition,
N2 may participate in reactions during gas phase decomposition of silicon and titanium source compounds.

The carrier gas is used to control the total gas pressure in the vessel containing the substrate, to control the mixing ratio of the vapors of the silicon, titanium, and nitrogen deposition source materials, to control the gas flux shape in the vessel, and or as N2+N2. It can be used to partially participate in the reaction, and Si3N4 containing Ti can be generated without using a carrier gas.

Next, a method for producing 5iJ4 containing Ti will be described in the case where 5t (J 141 TiCl 4 and NH) are used as raw materials and N2 is used as a carrier gas.

Said 5iCj! 4+ 'ricp 4 and N)1. are respectively introduced into the containers using, for example, a combination tube 4 as shown in FIG.
After that, the mixed gas of 5iCffi4 and TiC1 is introduced through the outer tube 9, and while surrounding the NH3 flux with the mixed gas of 5iC14, both gases are sprayed onto the substrate 2 in the container.

At this time, the carrier gas H! is sprayed through the outer tube 9 and 5iCjl! 4 and TiCJl! It is advantageous to premix with a.

The flow rate of N2 is preferably within the range of 100 to 7000 cc/min, and most suitably 1000 to 4000 cc/win. 5sCI! The flow rate (vapor state) of a is 20 to 10
Good within the range of 00cc/min, 50 to 500c/w
A range of in is most appropriate.

The flow rate of TiC1a (vapor state jlJt) is 0.1 to 100
Good within the range of cc/sin, 1 to 50 cc/sin
The most appropriate range is . The flow rate of NH3 is 50-5
Good within the range of 000c/n1in<, 80~400c
The most suitable range is c/II+in.

The total gas pressure in the container housing the substrate 2 is 1 to 760 mm
Hg is preferably within the range, and 5 to 1100IIIiH is optimal.

Note that even if the gas pressure is 1 atm or more, the Ti-containing Si of the present invention
3N4 can be manufactured.

(Example) Next, the relationship between the manufacturing conditions and the manufactured lumps will be explained.

Table 1 is a table showing an example of the influence of the manufacturing temperature on the crystal state of Si3N4 when producing the Si3N4 lumps of the present invention containing Ti and the Si3N4 lumps not containing Ti. Here, as manufacturing conditions other than the manufacturing temperature, if Ti is included, the gas pressure in the container is 39++nHg, Si (/
! 4 flow rate to 136 cc/a+tn (vapor B)
, TiCff1. The flow rate is 18 cc/sin (vapor state), NH, the flow rate is 120 cc/+in, 11, the flow rate is 2720 cc/sin, and when Ti is not included, the gas pressure in the container is 30+maHg, 5i (I2.
Flow rate: 136cc/5hin (steam state), NH
I flow rate is 120 cc/akin.

The H8 flow rate was set to 2720 cc/5 h.

Table 1 An example showing the relationship between manufacturing temperature and crystalline state of 5iJn As is clear from Table 1, when Ti is included, the temperature at which α-type crystals are formed is 300°C compared to when Ti is not included. It can be seen that β-type crystals, which have traditionally been difficult to produce by chemical vapor deposition, can be easily produced.

In the present invention, the TiN content in the agglomerates is 2 when the manufacturing temperature is 1100"C, as shown in FIG.
It is 8% by weight, but decreases to 4.2% by weight as the temperature rises further to 1500°C.

The density of Si3N containing Ti according to the present invention is 3 at a manufacturing temperature of 1100''C, as shown in FIG.
3 at a manufacturing temperature of 1500'C from 33 g/cs3
, to 24 g/cva', which decreases with increasing manufacturing temperature, but these density values are similar to those of TiN (theoretical density:
α-type 533N to contain 5.43 g/cm3);
The logical density of 3.18 g/cm3 is higher than that of β-type 5i3Nn, which is 3.19 g/cm3.

Next, the relationship between the manufacturing temperature and the micro-Vickers hardness when manufacturing the lump of the present invention will be explained with reference to FIG. When the manufacturing temperature is up to 1300°C, the higher the temperature, the higher the hardness, but when it exceeds 1300'C, the hardness decreases.

Next, FIG. 9 shows a comparison of the influence of the production temperature and gas pressure in the container on the crystalline state of the Ti-containing Si, N, agglomerates and the Ti-free 5iJ4 agglomerates of the present invention. According to the same figure, in the SiJ containing Ti of the present invention, in the lumps, A is made of amorphous, B is mainly made of amorphous and a small amount of α-type crystals, and D is mainly made of α-type crystals. Any of those E mainly consisting of β-type crystals,
Si, N which does not contain Ti.

It can be seen that it can be produced at a lower temperature compared to lumps.

Next, the present invention will be explained using more specific examples.

Using the apparatus shown in Fig. 10, a plate-shaped substrate 2 made of artificial graphite was sandwiched between copper electrodes 3, and the inside of the furnace was preliminarily 10-3 mm deep.
The Hg pressure was reduced, electricity was applied to the substrate, the substrate was heated to 500° C. or higher, and the substrate was degassed. Then the substrate temperature was increased to 14
Ammonia gas was flowed out from the inner tube at 120 cc/min, and at the same time hydrogen gas (flow rate 1360 cc/min) was passed through silicon tetrachloride (vapor pressure 76 mm Hg) at 0°C. win) and 20°C
A mixed gas of hydrogen gas (flow rate 1360 cc/5 in) passed through titanium tetrachloride (vapor pressure 10 txa Hg) was flowed out from the outer tube. Under these conditions, the flow rate of silicon tetrachloride gas was 136 cc/min, and the flow rate of titanium tetrachloride gas was 18 cc/+nin. Moreover, the pressure inside the container at that time was 30 mmHg. After flowing gas for 4 hours, the electric current was turned off, the mixture was cooled, and the substrate 2 inside was taken out, and a black 5iJ4 containing Ti with a thickness of 1.6 m was obtained on the surface of the substrate 2.

The characteristics of this Ti-containing Si3N were as follows.

Crystal structure = 91% by weight as determined by X-ray diffraction
It was a mixture of β type and α type at 9% by weight.

Crystal orientation: The (002) plane of the β type was oriented parallel to the substrate. The content of TiN was 4.3% by weight, and it was confirmed by a high-resolution electron microscope that TiN was precipitated in a columnar manner along the C-axis direction of β-type Si3N4. This Ti
The results of measuring other properties of 5iJa including 5iJa were as follows. Density 3.24 g/cm3, room temperature hardness: 20
00 kg/min (load fE100g), DC electrical conductivity 2 8 × 10-drop Ω-'c+s-' (70
0'C) eTable 2 provides a summary of various factors and their ranges for producing the Ti-containing Si3N4 agglomerates of the present invention.

Utilizing the excellent properties shown in Table 2 and above, the Ti-containing 5iaNa of the present invention can be used in the following fields.

1. As a coating material (a) By coating the surface of tool materials such as bits, dies, drills, cutters, etc., it extends the tool life and manages automatic machining systems (b) Wear resistance of bearings, gears, rotating shafts, etc. By coating the surfaces of mechanical parts that require high performance, it prevents wear and high-temperature seizure.

(c) By coating the surfaces of various materials such as metals, compounds, ceramics, graphite, etc., they are provided with highly hard surfaces and further improve mechanical properties at high temperatures (engine parts, turbine parts, etc.).

(d) By coating the surface of a substrate made of arbitrary material,
Conductivity is also imparted to a base made of an insulating material.

(e) Prevent the generation of static electricity by coating the surface of the insulator.

2. As a block material (f) It is useful as a tool material for carbide bits, carbide dies, etc.

(g) Used for hard physical and chemical instruments that require high hardness.

(H) It is useful for bearings, rotating shafts, bearings, and sealing materials that require high hardness and need to maintain that hardness at high temperatures.

(S) Can be used as a structural material used at high temperatures, such as engine parts and turbine parts.

(n) It can be used in heating elements that are lightweight and require high temperatures, such as thermal recording pens.

(Le) Can be used as a recorder for electrostatic printing equipment.

(wo) Used as a high-temperature filament.

(W) Used as a heating element for high temperatures.

[Brief explanation of the drawing]

Figure 1 is an X-ray diffraction pattern of the deposited surface of Si3N4 containing T1 of the present invention, and Figure 2 is a diagram related to Si and N4, which are mainly composed of β type with the (00f) plane oriented parallel to the substrate. FIG. 3 is a surface scanning electron micrograph of 5iJ4 containing Ti of the invention, and is a view related to 5isNa mainly composed of β type with the (001) plane oriented parallel to the substrate.
4 is a high-resolution electron micrograph of β-type Si3N containing β-type Si3N, (A) is a photograph of the 0-plane of β-type Si3N, (B) is a photograph of the plane containing the C-axis, and FIG. 4 is a photograph of the Ti of the present invention. Figure 5 is a perspective view of the spray pipe of the present invention, and Figure 6 is the 5iJn medium containing Ti of the present invention. FIG. 7 is a diagram showing the relationship between the density of Si and N containing Ti of the present invention and manufacturing temperature. FIG. 8 is a diagram showing the relationship between the density of Si and N containing Ti of the present invention and manufacturing temperature. A diagram showing the relationship between the hardness of the deposited surface at room temperature and the manufacturing temperature, FIG. 9 is a diagram showing the influence of the manufacturing temperature and the gas pressure in the container on the crystalline state of Si3N4, and FIG. It is a fragmentary cross-sectional view showing one example of a manufacturing device. 1... Container 2... Base 3... Gripping rod 4... Spraying tube 5... Vacuum gauge placement port 6... Door 7... Discharge port 8...
Inner tube 9... Outer tube drawing 4th degree of engraving (6C) IO: / Trg Kamai 70 Dotsu h-zu J further degree (K arti 154?- Figure 6 ν1 return (C) Fable 1 (Sacrilege) Figure 9

Claims (1)

[Claims] 1. Crystalline nitride consisting of at least 50% by weight of β-type crystals, including TiN precipitated in columnar shapes along the c-axis direction of the β-type crystals, and in which the (00l) plane of the β-type crystals is crystal oriented. Silicon block.