Highly integrated single electron devices and giga-bit lithography

Single electron transistors and memories for VLSI applications are fabricated and their characteristics are intensively investigated. It is shown that single electron transistors operating at room temperature are affected by quantum confinement effects and are very sensitive to the device size. Single electron memories with narrow channel MOSFETs also have large characteristics fluctuations. These results indicate that high resolution lithography with very high accuracy is strongly required for future giga-bit level single electron devices. MOSFETs with very narrow channel are also fabricated by electronbeam lithography, and the dependence of size fluctuations and drain current fluctuations on resist material is examined.