SILICON NITRIDE SINTERED BODY AND METHOD FOR PRODUCING SAME

摘要

A silicon nitride sintered body that contains silicon nitride, yttrium, magnesium and oxygen, and also contains a plurality of silicon nitride crystal grains and a grain boundary phase which constitutes a portion thereof other than the silicon nitride crystal grains, wherein: the grain boundary phase contains a Y20N4Si12O48 crystal phase, or the Y20N4Si12O48 crystal phase and a Y2Si3N3O4 crystal phase; and the ratio of the X-ray diffraction peak intensity of the (211) plane of the Y2Si3N3O4 crystal phase to the X-ray diffraction peak intensity of the (112) plane of the Y20N4Si12O48 crystal phase is 0 to 3.0, inclusive. As a result, the present invention provides a silicon nitride sintered body that exhibits high thermal conductivity and is favorable for use as a semiconductor device substrate or the like.