Abstract: According to one embodiment, an SiC semiconductor device comprises a p-type 4H—SiC region formed on at least part of a surface portion of an SiC substrate, a defect reduction layer formed on a surface portion of the 4H—SiC region, a gate insulating film formed on the defect reduction layer, and a gate electrode formed on the gate insulating film. The defect reduction layer has the C defect density that is defined as follows and is set to Cdef<1015 cm?3 by introduction of carbon.

Abstract: A master node (12) sends an identification signal for designating a communication channel in an identification signal time slot. When the own node matches the node in which the communication channel designated by the identification signal sent from the master node (12) is set in the identification signal time slot, the master node (12) and slave nodes (131 to 13n) each perform data transmission via the communication channel, based on the set contents of the communication channel, in the data transmission time slot corresponding to the identification signal time slot in which the identification signal has been sent.