Abstract: A silicon carbide substrate has a high-frequency loss equal to or less than 2.0 dB/mm at 20 GHz is effective to mount and operate electronic components. The silicon carbide substrate is heated at 2000° C. or more to be reduced to the high-frequency loss equal to 2.0 dB/mm or less at 20 GHz. Moreover, manufacturing the silicon carbide substrate by CVD without flowing nitrogen into a heater enables the high-frequency loss to be reduced to 2.0 dB/mm or less.

Abstract: A base is formed of a material, such as SiC, having mechanical characteristics higher than those of silicon for forming a semiconductor layer, and the base and the semiconductor layer are bonded through an insulating layer. After bonding, an SOI substrate is formed by mechanically separating the semiconductor layer from the base, and the separated semiconductor layer is reused for forming the subsequent SOI substrate. Thus, a large SOI substrate having a diameter of 400 mm or more, which has been difficult to obtain by conventional methods, can be obtained.

Abstract: A silicon carbide substrate has a high-frequency loss equal to or less than 2.0 dB/mm at 20 GHz is effective to mount and operate electronic components. The silicon carbide substrate is heated at 2000° C. or more to be reduced to the high-frequency loss equal to 2.0 dB/mm or less at 20 GHz. Moreover, manufacturing the silicon carbide substrate by CVD without flowing nitrogen into a heater enables the high-frequency loss to be reduced to 2.0 dB/mm or less.

Abstract: A silicon carbide product is disclosed which is characterized by having a surface with a metal impurity concentration of not more than 1×1011 (atoms/cm2). Also disclosed are a method for producing such a silicon carbide product and a method for cleaning a silicon carbide product. A silicon carbide having such a highly cleaned surface can be obtained by cleaning it with a hydrofluoric acid, a hydrochloric acid, or an aqueous solution containing a sulfuric acid and a hydrogen peroxide solution. The present invention provides a highly cleaned silicon carbide, and thus enables to produce a semiconductor device which is free from consideration on deterioration in characteristics caused by impurities. Further, when the silicon carbide is used in a unit for semiconductor production or the like, there is such an advantage that an object processed in the unit can be prevented from suffering an adverse affect of flying impurities.