Epitaxial growth method for silicon carbide
View Patent ↗The present invention provides a method of epitaxial growth of an SiC thin film by the thermal CVD process wherein it is possible to improve the in-plane uniformity of the doping density and possible to grow an SiC thin film by a uniform thickness. This method is an epitaxial growth method for silicon carbide characterized by comprising adjusting a ratio of the hydrocarbon gas and silicon feedstock gas so as to become, by C/Si ratio, 0.5 to 1.5 in range, making the hydrocarbon gas contact a hydrocarbon decomposition catalyst heated to 1000° C. to 1200° C. so as to make at least part of the hydrocarbon gas break down into carbon and hydrogen, and supplying carbon contained in the hydrocarbon gas and silicon contained in the silicon feedstock gas to the silicon carbide single crystal substrate.
1. An epitaxial growth method for silicon carbide making a hydrocarbon gas and silicon feedstock gas react by a thermal chemical vapor deposition (CVD) process to thereby form a silicon carbide thin film on a silicon carbide single crystal substrate, the epitaxial growth method for silicon carbide comprising:
adjusting a ratio of the hydrocarbon gas and silicon feedstock gas so as to become, by C/Si ratio, in the range of 0.5 to 1.5,
making the hydrocarbon gas contact a hydrocarbon decomposition catalyst heated to 1000° C. to 1200° C. so as to make at least part of the hydrocarbon gas break down into carbon and hydrogen, and
making carbon contained in the hydrocarbon gas and silicon contained in the silicon feedstock gas react at 1500° C. to less than 1800° C. in temperature on the silicon carbide single crystal substrate and form a silicon carbide thin film,
wherein a thickness of the silicon carbide thin film formed on the silicon carbide single crystal substrate is 3 μm to 100 μm, an in-plane uniformity of thickness of the silicon carbide thin film is in a range from 0.45 to 1.9%, and an in-place uniformity of doping density of the silicon carbide thin film is in a range from 2.2 to 4.1%.
2. The epitaxial growth method for silicon carbide according to claim 1 , wherein the ratio of the amount of the hydrocarbon gas made to contact the hydrocarbon decomposition catalyst and decompose in the total amount is 50% or more.
3. The epitaxial growth method for silicon carbide according to claim 1 , wherein the hydrocarbon decomposition catalyst comprises at least one type of metal selected from ruthenium, rhodium, palladium, platinum, copper, titanium, zirconium, and hafnium or an alloy comprised of at least two types of elements of the group of metal elements.
4. The epitaxial growth method for silicon carbide according to claim 1 , wherein the hydrocarbon decomposition catalyst is provided with a sheet shaped contact surface contacting the hydrocarbon gas.
5. The epitaxial growth method for silicon carbide according to claim 1 , wherein the hydrocarbon gas is one or more types of gas selected from a group comprising methane, ethane, propane, butane, ethylene, and acetylene.
6. The epitaxial growth method for silicon carbide according to claim 1 , wherein the silicon feedstock gas is one or more types of gas selected from a group comprising silane, disilane, trichlorosilane, dichlorosilane, and silicon tetrachloride.
7. The epitaxial growth method for silicon carbide according to claim 1 , wherein the hydrocarbon gas is made to contact the hydrocarbon decomposition catalyst in a state of mixed feedstock gases comprising the hydrocarbon gas and the silicon feedstock gas mixed together.