| abstract |
Provided is a method for producing a silicon nitride substrate, said method comprising: a raw material powder preparation step of preparing a raw material powder containing a silicon powder, a rare earth element compound and a magnesium compound, wherein, when the amount of silicon in the raw material powder is expressed in terms of a silicon nitride content, the raw material powder contains the rare earth element compound in an amount of 1 to 7 mol% inclusive in terms of an oxide content and also contains the magnesium compound in an amount of 8 to 15 mol% inclusive in terms of an oxide content; a sheet molding step of molding the raw material powder into a sheet-like shape to form a sheet-like article; a nitriding step of heating the sheet-like article in a nitrogen atmosphere at 1200 to 1500°C inclusive to nitride silicon contained in the sheet-like article; and a sintering step of sintering the sheet-like article, which has been undergone the nitriding step, under a nitrogen atmosphere. |