A kind of film coating apparatus of single-crystal silicon carbide sheet
Technical field
The utility model relates to a kind of film coating apparatus of single-crystal silicon carbide sheet.
Background technology
With the wide-band gap material that SiC and GaN is representative, it is the third generation semi-conductor after Si and GaAs.Compared with Si and GaAs, SiC has broad stopband (2 ~ 3 times of 2.2 ~ 3.3eV, Si), high heat conductance (3 ~ 3.3 times of Si), high breakdown field strength (4 × 10
6v/cm, Si 10 times), high saturated electrons drift speed (2.5 × 10
7cm/s, Si 2.5 times), chemically stable, high rigidity is resistance to worn, and the advantage such as high bonding energy.So SiC is particularly suitable for manufacturing high temperature, high frequency, superpower, radioprotective, erosion-resisting electron device.SiC device can be used for the key areas such as man-made satellite, rocket, radar and communication, re-entry space vehicle, seafari, earthquake prediction, petroleum drilling, mechanical workout and automotive circuit diagram.In addition, six side SiC and GaN lattice and thermal expansion match, and are the desirable substrate material manufacturing the luminous and laser diode of high brightness GaN at present.
At present adopt bonding method with the seed crystal of vapor phase process growth SiC crystal in principle, bonding seed crystal carries out the technology of high temperature sintering under weight, and the seed crystal that this technology obtains carries out growing and brings unpredictable result to the process of crystal growth:
One, because seed crystal and back side graphite linings belong to two kinds of different materials, the thermal expansivity difference of this bi-material is comparatively large, causes the crystal stress of growth comparatively large like this, thus causes the crystal ingot of growth easily to occur crackle, and easily ftracture when coming out of the stove.
Two, the glue trace due to bonding is uneven, and crystal growth exists the warm field difference of local early stage, causes seed crystal to be inoculated and occurs many types of phenomenon.
Utility model content
For prior art Problems existing, one of the purpose of this utility model is the film coating method providing a kind of single-crystal silicon carbide sheet, one deck carbon film is deposited in seed crystal face, seed crystal after plated film effectively can overcome the shortcoming of above-mentioned single crystal growing existence in early stage, according to PECVD (Plasma Enhanced Chemical VaporDeposition, plasma enhanced chemical vapor deposition method) square ratio juris, control the thickness of single-chip coatings easily, mass simultaneous carry out seed crystal plated film, and without the need to carrying out large scrap build, excellent single crystal growing seed crystal source can be obtained.The quality in early stage of single crystal growing can be improved significantly.Two of the purpose of this utility model there are provided the film coating apparatus realizing above-mentioned film coating method.
For achieving the above object, the film coating method of a kind of single-crystal silicon carbide sheet of the utility model, the method comprises the steps:
Step 1) silicon carbide wafer is placed in vacuum tightness is 10
-2in the graphite treatment chamber of Pa;
Step 2) in chamber, described graphite place, be filled with 60000Pa rare gas element;
Step 3) by ruhmkorff coil, coupling heating is carried out to graphite treatment chamber, the pressure after a predetermined time in slow reduction graphite treatment chamber is to 1000Pa-3000Pa;
Step 4) maintain pressure in graphite treatment chamber, in chamber, be filled with rare gas element and methane gas, after methane gas cracking, form carbon film on silicon carbide wafer surface.
Further, by controlling described step 3) and step 4) described in pressure in graphite treatment chamber control the thickness of described carbon film, the larger carbon film layer of pressure is thinner, and the less carbon film layer of pressure is thicker.
Further, burn processing is carried out to from expellant gas in described graphite treatment chamber.
Further, described step 3) in the scheduled time be 30 minutes.
Further, described rare gas element is argon gas.
A kind of film coating apparatus realizing the single-crystal silicon carbide sheet of aforesaid method, this device comprises body of heater, described body of heater arranged outside has ruhmkorff coil, graphite treatment chamber is provided with in body of heater, silicon carbide wafer is placed in described graphite treatment chamber, body of heater is provided with the inlet mouth and bleeding point that connect graphite treatment chamber, described inlet mouth and described bleeding point is provided with valve, hermetic seal in graphite treatment chamber during described valve closes.
Further, heat preserving and insulating material is coated with outside the chamber wall in described graphite treatment chamber.
Further, described heat preserving and insulating material arranged outside has water-cooling sandwich, and described water-cooling sandwich is made up of double-deck silica tube, between the internal layer and skin of this silica tube, be connected with water coolant.
Further, be connected with mechanical pump with described bleeding point, the exit end of described mechanical pump is provided with lighter for ignition.
The film coating method of single-crystal silicon carbide sheet of the present utility model and device are placed in the silica tube of Double water-cooled by graphite treatment chamber, between graphite treatment chamber and layered quartz tube, only add necessary lagging material, and without the need to very large vacuum chamber.Water-cooling sandwich is used for leading to the graphite treatment chamber cooling water-cooled silica tube inwall.Can carry out bleeding and being vented by bleeding point, by the aperture of valve to reach the pressure maintaining graphite treatment chamber.Graphite treatment chamber is in treatment unit center, and thermal insulation material is around used for insulation, and skin is ruhmkorff coil.Electric current in ruhmkorff coil directly can be coupled out induced current by thermal insulation material on graphite treatment chamber, thus reaches the temperature of 1100-1900 DEG C be heated to by treatment chamber needed for wafer plated film.The feature of the method and device conveniently by adjusting the proportioning of charge flow rate, the size of pressure, the length of plated film time, can change wafer coatings thickness object in treating chamber; Simultaneously due to the minimizing in silica tube space, heat exchanger effectiveness in graphite treatment chamber is improved greatly, the size of ruhmkorff coil can design larger, and graphite treatment chamber size add on a large scale change, the coupling that both still can have, thus without the need to carrying out large scrap build, wafer plated film can be carried out in batches.
Accompanying drawing explanation
Fig. 1 is structural representation of the present utility model.
Embodiment
Below, with reference to accompanying drawing, the utility model is more fully illustrated, shown in the drawings of exemplary embodiment of the present utility model.But the utility model can be presented as multiple multi-form, and should not be construed as the exemplary embodiment being confined to describe here.But, these embodiments are provided, thus make the utility model comprehensively with complete, and scope of the present utility model is fully conveyed to those of ordinary skill in the art.
For ease of illustrating, here can use such as " on ", the space relative terms such as D score " left side " " right side ", for illustration of the element of shown in figure or the feature relation relative to another element or feature.It should be understood that except the orientation shown in figure, spatial terminology is intended to comprise device different azimuth in use or operation.Such as, if the device in figure is squeezed, be stated as the element being positioned at other elements or feature D score will be positioned at other elements or feature " on ".Therefore, exemplary term D score can comprise upper and lower both orientation.Device can otherwise be located (90-degree rotation or be positioned at other orientation), and space used here illustrates relatively can correspondingly explain.
Be illustrated in figure 1 a kind of film coating apparatus of single-crystal silicon carbide sheet, this device comprises body of heater, body of heater arranged outside has ruhmkorff coil 5, body of heater comprises upper flange 2, double-deck silica tube 4 and lower flange 3, water coolant is connected with in the interlayer 3 of double-deck silica tube 4, graphite treatment chamber 13 is provided with in double-deck silica tube 4, heat preserving and insulating material 14 is filled with between graphite treatment chamber 13 and silica tube 4, graphite holders 12 is provided with in graphite treatment chamber 13, silicon carbide wafer 6 is arranged on graphite holders 12, upper flange 2 is provided with inlet mouth 1, inlet mouth 1 is connected with graphite treatment chamber 13, inlet mouth 1 is provided with valve 15, lower flange 11 is connected with bleeding point 7, bleeding point 7 is connected with graphite treatment chamber 13, bleeding point 7 is provided with valve 8, hermetic seal in graphite treatment chamber 13 when valve 15 and 8 is closed, the aperture of regulated valve 15 and 8 can control the vacuum tightness in graphite treatment chamber 13, mechanical pump 9 is connected with bleeding point 7, the exit end of mechanical pump 9 is provided with lighter for ignition 10, for burning by expellant gas in graphite treatment chamber 13.
Embodiment 1
Double-deck silica tube layered quartz tube internal diameter is 184 millimeters, is highly 510 millimeters, ruhmkorff coil internal diameter 240 millimeters, height 386 millimeters, graphite treatment chamber internal diameter 130 millimeters, height 190 millimeters.In graphite chamber, put a graphite holders, the wafer of needs is put on support, puts a graphite cover with holes at the top in graphite chamber, and the surrounding on graphite cover and graphite chamber uses thermal insulation material graphite carbon felt parcel.Then treatment chamber is bled, make its vacuum tightness reach 10
-2after Pa, be filled with the high-purity Ar of 60000Pa.Open intermediate frequency power supply, control output rating 8Kw, wait for after 15 minutes, open mechanical pump, in 30 minutes by the Pressure Drop for the treatment of chamber to 1000Pa, maintain this pressure constant, fill high-purity Ar and methane (CH4), open lighter for ignition and carry out exhaust combustion process, process 1h.Result shows that wafer thickness is about 710nm.
Embodiment 2
Double-deck silica tube layered quartz tube internal diameter is 184 millimeters, is highly 510 millimeters, ruhmkorff coil internal diameter 240 millimeters, height 386 millimeters, graphite treatment chamber internal diameter 130 millimeters, height 190 millimeters.In graphite chamber, put a graphite holders, the wafer of needs is put on support, puts a graphite cover with holes at the top in graphite chamber, and the surrounding on graphite cover and graphite chamber uses thermal insulation material graphite carbon felt parcel.Then treatment chamber is bled, make its vacuum tightness reach 10
-2after Pa, be filled with the high-purity Ar of 60000Pa.Open intermediate frequency power supply, control output rating 8Kw, wait for after 15 minutes, open mechanical pump, in 30 minutes by the Pressure Drop for the treatment of chamber to 1500Pa, maintain this pressure constant, fill high-purity Ar and methane (CH4), open lighter for ignition and carry out exhaust combustion process, process 1h.Result shows wafer thickness 626nm.
Embodiment 3
Double-deck silica tube layered quartz tube internal diameter is 184 millimeters, is highly 510 millimeters, ruhmkorff coil internal diameter 240 millimeters, height 386 millimeters, graphite treatment chamber internal diameter 130 millimeters, height 190 millimeters.In graphite chamber, put a graphite holders, the wafer of needs is put on support, puts a graphite cover with holes at the top in graphite chamber, and the surrounding on graphite cover and graphite chamber uses thermal insulation material graphite carbon felt parcel.Then treatment chamber is bled, make its vacuum tightness reach 10
-2after Pa, be filled with the high-purity Ar of 60000Pa.Open intermediate frequency power supply, control output rating 8Kw, wait for after 15 minutes, open mechanical pump, in 30 minutes by the Pressure Drop for the treatment of chamber to 2000Pa, maintain this pressure constant, fill high-purity Ar and methane (CH4), open lighter for ignition and carry out exhaust combustion process, process 1h.Result shows wafer thickness 594nm.
Embodiment 4
Double-deck silica tube layered quartz tube internal diameter is 184 millimeters, is highly 510 millimeters, ruhmkorff coil internal diameter 240 millimeters, height 386 millimeters, graphite treatment chamber internal diameter 130 millimeters, height 190 millimeters.In graphite chamber, put a graphite holders, the wafer of needs is put on support, puts a graphite cover with holes at the top in graphite chamber, and the surrounding on graphite cover and graphite chamber uses thermal insulation material graphite carbon felt parcel.Then treatment chamber is bled, make its vacuum tightness reach 10
-2after Pa, be filled with the high-purity Ar of 60000Pa.Open intermediate frequency power supply, control output rating 8Kw, wait for after 15 minutes, open mechanical pump, in 30 minutes by the Pressure Drop for the treatment of chamber to 2500Pa, maintain this pressure constant, fill high-purity Ar and methane (CH4), open lighter for ignition and carry out exhaust combustion process, process 1h.Result shows wafer thickness 480nm.
Embodiment 5
Double-deck silica tube layered quartz tube internal diameter is 184 millimeters, is highly 510 millimeters, ruhmkorff coil internal diameter 240 millimeters, height 386 millimeters, graphite treatment chamber internal diameter 130 millimeters, height 190 millimeters.In graphite chamber, put a graphite holders, the wafer of needs is put on support, puts a graphite cover with holes at the top in graphite chamber, and the surrounding on graphite cover and graphite chamber uses thermal insulation material graphite carbon felt parcel.Then treatment chamber is bled, make its vacuum tightness reach 10
-2after Pa, be filled with the high-purity Ar of 60000Pa.Open intermediate frequency power supply, control output rating 8Kw, wait for after 15 minutes, open mechanical pump, in 30 minutes by the Pressure Drop for the treatment of chamber to 3000Pa, maintain this pressure constant, fill high-purity Ar and methane (CH4), open lighter for ignition and carry out exhaust combustion process, process 1h.Result shows wafer thickness 390nm.