CN101442010A

CN101442010A - Method for growing silicon carbide thick film on graphical substrate

Info

Publication number: CN101442010A
Application number: CNA2007101777811A
Authority: CN
Inventors: 赵永梅; 孙国胜; 刘兴昉; 王亮; 王雷; 赵万顺; 李晋闽; 曾一平
Original assignee: Institute of Semiconductors of CAS
Current assignee: Institute of Semiconductors of CAS
Priority date: 2007-11-21
Filing date: 2007-11-21
Publication date: 2009-05-27

Abstract

The invention relates to a method for growing a SiC thick film on a pattern substrate. The method comprises the following steps: firstly, obtaining a pattern from the silicon substrate by adopting photoetching technology, wherein the mask plate pattern is of a parallel long strip shape or a square table top or a combined pattern thereof; and secondly, growing the SiC film on the pattern substrate by a chemical vapor deposition method. The SiC film produced by the method grows in a transverse combined mode at a window area while longitudinally growing in vertical table top direction, can reduce the defects of an extension layer of silicon carbide, and improve the quality of an extending silicon carbide crystal; meanwhile, a hollow structure formed after the window area is combined can release stress, solve the problem of wafer warp caused by large mismatching between the silicon substrate and the silicon carbide, and has important application value in large area thick-film growth and rapid grow technology of the silicon carbide.

Description

The method of growing silicon carbide thick film on graphical substrate

Technical field

The present invention relates to technical field of semiconductors, particularly relate to a kind of method of growing silicon carbide thick film on graphical substrate.

Background technology

Carborundum has broad-band gap, high disruptive field intensity, and high heat conductance, high saturated electrons drift speed, fabulous characteristics such as physical and chemical stability have advantageous advantage in applications such as high temperature, high frequency, high-power, radioresistances.Carborundum can obtain on silicon substrate in epitaxial growth, and silicon substrate has high crystal mass, and large tracts of land and cheap can overcome the expensive deficiency of the required substrate of carborundum homoepitaxy; Simultaneously again can be compatible mutually with the silica-based lsi technology of maturation.So heteroepitaxial growth carborundum becomes at present the focus of research both at home and abroad on the silicon substrate.

Yet owing to have big lattice mismatch (20%) and thermal mismatching (8%) between carborundum and the silicon, epitaxial growth carborundum can exist a large amount of misfit dislocations, stacking fault, line defect, twin etc. on the silicon, influences the crystal mass of carborundum; And because the existence of the stress that big mismatch causes causes that very easily chip warpage or rete come off when realizing the growth of carborundum large tracts of land and thick film.

The graph substrate growing silicon carbide thick film is to make figure on silicon substrate, carries out growth of silicon carbide then on patterned substrate.Behind etching figure on the silicon substrate, comprise mesa region and window area on the silicon substrate.During growth of silicon carbide, the longitudinal growth of mesa region and window area and laterally merging can suppress the extension of dislocation etc. effectively, reduce the epitaxial loayer defect concentration, improve crystal mass; Laterally merge the back and can discharge stress effectively at the hollow structure that window area produces.

The present invention adopt the graph substrate technology solve carborundum on silicon substrate during heteroepitaxial growth because chip warpage that big lattice mismatch and thermal mismatching produce and rete come off problem, being applied to carbofrax material growth and device development field is a highly effective technology.

Summary of the invention

The object of the present invention is to provide the method for a kind of employing graph substrate growing silicon carbide (SiC) thick film.

Technical solution of the present invention: at first adopt photoetching technique to etch figure on silicon substrate, figure is parallel long strip or square table top or their composite figure; Adopt a kind of low-pressure chemical vapor deposition device growing silicon carbide thick film on this patterned silicon substrate.

Mechanism of the present invention and technical characterstic: the graph substrate technology is to etch figure on substrate, and figure is made up of window area and mesa region.During epitaxial growth, gas atom reacts nucleation on table top, and the part that is etched on the substrate is that window area is because the migration of atom needs the regular hour, so be difficult for nucleation.Rete in longitudinal growth, also carries out cross growth along the growth of vertical table-board direction.Along with the growth of thick film, the cross growth zone of adjacent table top can reach merging, and epitaxial loayer just can cover the entire substrate surface after cross growth acquires a certain degree.The graph substrate technology is utilized the merging of longitudinal growth and cross growth, can reduce or suppress the extension of dislocation at epitaxial loayer, thereby improves the crystal mass of epitaxial loayer.The hollow structure that laterally merges back formation at window area can discharge stress, the chip warpage problem that reduction or inhibition substrate and the big mismatch of epitaxial loayer cause, especially be fit to be applied to obtain high-quality silicon carbide epitaxial layers in carborundum large area deposition and the quick thick film growing technology.

Adopt the present invention to carry out the heteroepitaxial growth of silicon carbide thick film on the silicon substrate, can obtain high-crystal quality, non-warpage, rete does not have the silicon carbide thick film that comes off.The present invention provides a highly effective material growing technology for the related device development of carbofrax material.

Description of drawings

Fig. 1 a is the floor map of parallel long strip mask structure among the present invention;

Fig. 1 b is the cross section structure schematic diagram of silicon carbide epitaxial growth on the graph substrate of the present invention;

Fig. 2 a and Fig. 2 b are the sem photographs of the carborundum of growing on the patterned silicon substrate of the present invention;

Fig. 3 is the X-ray diffraction test result of the carborundum of growing on the patterned silicon substrate of the present invention.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.

The present invention adopts a kind of patterned substrate technology growing silicon carbide (SiC) thick film on silicon substrate, may further comprise the steps:

To be 111 or 100 silicon substrate clean the back through the silicon wet chemistry cleaning method of standard in the crystal orientation adopts photoetching technique to etch figure on substrate, the mask figure is parallel long flagpole pattern or square table top or their composite figure, and wherein parallel long list structure figure can consult shown in Fig. 1 a.The window area width of figure is 1～20 μ m, and etching depth is 1～10 μ m, and the mesa region width is 1～20 μ m; Wherein graphic length is 50～200 μ m in the parallel long flagpole pattern.

Patterned silicon substrate is put into the low-pressure chemical vapor deposition device, heat up in hydrogen environment and carry out the hydrogen etching processing, temperature is 1100 ℃; Hydrogen flowing quantity is 5～20 standard liter/min; Hydrogen etching pressure is 5000～15000 Pascals; The hydrogen etch period is 4～6 minutes.

The hydrogen etching finishes the back intensification and carries out silicon carbide epitaxial growth, and growth temperature is 1200～1350 ℃; Source gas is ethene (or propane) and silane; The flow of ethene (or propane) is 1.5～6 standard ml/min, and the flow of silane is 0.5～2 standard ml/min; Pressure is 5000～15000 Pascals during growth.

Behind the growth ending, close silane and ethene (or propane), under hydrogen environment, be cooled to room temperature.

Key of the present invention is to adopt patterned silicon substrate to carry out silicon carbide epitaxial growth, improved the crystal mass of silica-based carborundum heteroepitaxial growth, the hollow structure of the horizontal merging growth district generation on this patterned substrate can be used for discharging the stress that big mismatch causes simultaneously, the warpage of wafer and the problem that comes off of rete in minimizing or the growth of inhibition thick film provide possibility for further increasing the silicon carbide epitaxy layer thickness with raising epitaxial loayer crystal mass.

Be a specific embodiment below, step is as follows:

Choose Si (100) substrate, adopt the silicon wet chemistry cleaning method of standard to clean silicon substrate.

Adopt photoetching technique and dry etching technology to etch figure on silicon substrate, the mask figure of employing is the parallel long flagpole pattern, and length is 100 μ m, window area is of a size of 2 μ m, 3 μ m and 5 μ m, and mesa region is of a size of 2 μ m, 3 μ m and 5 μ m, window area etching depth are 5 μ m.

Patterned silicon substrate is put into the low-pressure chemical vapor deposition system, be warming up to 1100 ℃ and carried out the hydrogen etching processing 5 minutes, hydrogen flowing quantity is 5 standard liter/min, and pressure is 5300 handkerchiefs during etching.

Be warming up to 1300 ℃, feed ethene and silane, carry out the silicon carbide layer epitaxial growth.The flow of therein ethylene and silane is respectively 3 standard ml/min and 1 standard ml/min.

Behind the growth ending, close silane and ethene, be cooled to room temperature under the hydrogen shield.

Adopt the epitaxially grown silicon carbide thick film surfacing on silicon substrate of this technology, as bright as a sixpence, wafer does not have obvious warping phenomenon, and microscopically is observed no a large amount of crackles.Silicon carbide epitaxial growth laterally merges the cross section structure schematic diagram shown in Fig. 1 b on the graph substrate.The sem photograph of the carborundum of growing on the graph substrate that adopts field emission scanning electron microscope to observe is shown in Fig. 2 a and Fig. 2 b.The carborundum of growing on the graph substrate that adopts X-ray diffraction to test as shown in Figure 3.

So far invention has been described in conjunction with the preferred embodiments.Should be appreciated that those skilled in the art can carry out various other change, replacement and interpolations under the situation that does not break away from the spirit and scope of the present invention.Therefore, scope of the present invention is not limited to above-mentioned specific embodiment, and should be limited by claims.

Claims

1. the method for a growing silicon carbide thick film on graphical substrate is characterized in that, comprises the steps:

1) adopt photoetching technique etch silicon substrate to obtain patterned silicon substrate;

2) adopt the chemical gaseous phase depositing process growing silicon carbide thick film;

2. the method for growing silicon carbide thick film on graphical substrate according to claim 1 is characterized in that, the crystal orientation of described silicon substrate is 111 or 100.

3. the method for growing silicon carbide thick film on graphical substrate according to claim 1 is characterized in that, adopts photoetching technique and wet method or the described silicon substrate of dry etching technology etching.

4. the method for growing silicon carbide thick film on graphical substrate according to claim 3, it is characterized in that, in described photoetching technique and wet method or the dry etching technology, the mask figure is parallel long strip or square table top or their composite figure, the window area width is 1～20 μ m, etching depth is 1～10 μ m, and the mesa region width is 1～20 μ m; Wherein graphic length is 50～200 μ m in the parallel long flagpole pattern.

5. the method for growing silicon carbide thick film on graphical substrate according to claim 1 is characterized in that, the described silicon carbide thick film of growing adopts low-pressure chemical vapor deposition method.

6. the method for growing silicon carbide thick film on graphical substrate according to claim 5, it is characterized in that, in the described low-pressure chemical vapor deposition method, growth pressure is 5000～15000 Pascals, growth temperature is 1200～1350 ℃, the ethene flow is 1.5～6 standard ml/min, and silane flow rate is 0.5～2 standard ml/min.