A titanium target assembly includes a titanium sputtering target, a copper or copper alloy backing plate and serving as a support member for the target and a silver or silver alloy coating film and formed between the target and backing plate. In the encryption key generating method, an encryption key corresponding to data in the lowest hierarchies of hierarchical scalabilities is divided as a master key by the number of hierarchies in scalability. A first shorting bar is formed on the gate insulating film, located between the gate lines and the gate shorting bar, and connected to the odd gate lines. Said arrangement is specifically adapted to prevent a protection resistor from warming up to too high a surface temperature in the case of an error, because the current is flowing for too much time. The tip cap may be formed from a ceramic matrix composite material. The device comprises a wafer of a semiconductor material covered with a conductive layer arranged parallel to the support, the wafer being connected to the support by conductive pillars distributed around each circuit portion and in contact with the conductive layer.