There are provided a substrate for an inkjet head, an inkjet head, and an inkjet printing apparatus wherein in a case where current is carried through a protection layer for heating resistors, electrical connection to its periphery is prevented without fail. The optical storage medium is applicable in an optical read or write system with blue laser having a wavelength in between 385 nm to 425 nm and an objective lens with numerical aperture greater than 0. The prism assembly also includes a third prism having a third front face parallel to the second rear face, a third side face, and a third rear face. An ion beam etching process is performed using an oxygen-containing source gas to remove etching by-products on sidewalls of the magnetic tunnel junction structure and to oxidize the sidewalls of the magnetic tunnel junction structures. The silicon carbide layer includes: a body region having a first conductivity type and facing a gate electrode with the gate insulating film being interposed therebetween; and a pair of regions separated from each other by the body region and having a second conductivity type. The display system includes a display apparatus equipped with a wireless communication function, and a human input device connected with the display apparatus to transmit user input data to the display apparatus.