A semiconductor system includes a controller outputting a clock, a chip selection signal, a command address, and data, and a semiconductor device performing an auto-refresh operation when the chip selection signal and command address input in synchronization with the clock have a combination for performing the auto-refresh operation, correcting an error of internal data stored therein by performing a read-modify-write operation instead of the auto-refresh operation when the auto-refresh operation is performed a first set number of times and storing the corrected internal data, performing a self-refresh operation when the chip selection signal and command address input in synchronization with the clock have a combination for performing the self-refresh operation, and correcting an error of the internal data stored therein by performing a read-modify-write operation instead of the self-refresh operation when the self-refresh operation is performed a second set number of times and to store the corrected internal data.