A multi-chip semiconductor package and a fabrication method thereof are provided. A sampling unit of the implantable medical device records electrogram samples for the different implantable electrodes to get different sample sets. A group III-nitride crystal substrate attaining a small absorption coefficient and the method of manufacturing the same, as well as a group III-nitride semiconductor device can thus be provided. The weighted component analysis results may represent the respective image data as a weighted sum of components. The inserting portion is adapted to be inserted into the cavity.