Field-effect induced electron channels in a Si/Si0.7Ge0.3 heterostructure

Abstract
Size effects in field‐effect induced wires imposed upon a high‐mobility Si/Si0.7Ge0.3 heterostructure were studied by magnetotransport. Spatial 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 ≤0 V. This maximum results from diffuse boundary scattering and proves the existence of spatially separated electron channels. From its position wire widths varying from 0.14 to 0.28 μm can be estimated.