| 摘要 |
An object of the present invention is to provide a silicon nitride sintered body having high mechanical strength and thermal conductivity, and a circuit substrate using the same. A method for producing a silicon nitride powder, including heating an amorphous Si-N(-H)-based compound in which assuming that the specific surface area is RS (m 2 /g) and the oxygen content ratio is RO (mass%), RS/RO is 500 or more, at a temperature rising rate of 12 to 100°C/min in a temperature range from 1,000 to 1,400°C while flowing the compound by a continuous firing furnace, is provided. Also, a silicon nitride powder wherein assuming that the content ratio of oxygen existing in a region from the particle surface to 3 nm beneath the particle surface is FSO (mass%), the content ratio of oxygen existing in the more inward side than 3 nm beneath the particle surface is FIO (mass%), and the specific surface area is FS (m 2 /g), FS/FSO is from 8 to 25 and FS/FIO is 22 or more; a silicon nitride sintered body obtained by sintering the silicon nitride powder; and a circuit substrate using the silicon nitride sintered body, are provided. |
