FIELD-EFFECT INDUCED ELECTRON CHANNELS IN A SI SI0.7GE0.3 HETEROSTRUCTURE/

Size effects in field-effect induced wires imposed upon a high-mobilit y Si/Si0.7Ge0.3 heterostructure were studied by magnetotransport. Spat ial separation of the electron channels was accomplished by means of a periodically modulated Schottky gate. The magnetoresistance parallel to the wires shows a well-pronounced peak at magnetic fields <0.3 T at a gate bias less than or equal to 0 V. This maximum results from diff use boundary scattering and proves the existence of spatially separate d electron channels. From its position wire widths varying from 0.14 t o 0.28 mu m can be estimated.