Kabushiki Kaisha Toshiba

Eiji Toyoda

Tsutomu Tezuka

Soichiro Hayashi

A method for manufacturing a field effect transistor, includes: forming a mask of an insulating film on a semiconductor layer containing Si formed on a semiconductor substrate; forming the semiconductor layer into a mesa structure by performing etching with the use of the mask, the mesa structure extending in a direction parallel to an upper face of the semiconductor substrate; narrowing a distance between two sidewalls of the mesa structure and flattening the sidewalls by performing a heat treatment in a hydrogen atmosphere, the two sidewalls extending in the direction and facing each other; forming a gate insulating film covering the mesa structure having the sidewalls flattened; forming a gate electrode covering the gate insulating film; and forming source and drain regions at portions of the mesa structure, the portions being located on two sides of the gate electrode.

Field effect transistor and method for manufacturing the same

A superconducting system including a superconductive coil and a perpetual current switch connected in parallel therewith in a cryogenic vessel, wherein the perpetual current switch includes a superconductive lead and a heater that causes the superconductive lead to be normal-conductive; and a DC power source that can arbitrarily change the output thereof with respect to the superconductive coil and the perpetual current switch. The system circulates a current of a specified amount within a closed loop constituted by the superconductive coil and the superconductive lead so as to create a perpetual current loop. The system further includes a reference generator unit provided with a current reference value that has a first sweep gradient and changes the superconductive coil current, an established current value such that the superconductive coil current is caused to reach a specified target value, a current reference value that has a second sweep gradient and does not change the superconductive coil current after the arrival thereof at the target value but changes currents that respectively flow into the DC power source and the superconductive lead; and a timing control unit that switches with specified changeover timings the two current reference values and the heater-energizing periods.

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Niigata-ken, Japan

Eiji Toyoda