Size effect of nanometer structure devices are reviewed, placing main emphasis on (i) drift velocity overshoot, (ii) hot electron effect in short MOSFET, (iii) high field transport of two dimensional electrons in MOS inversion layers, (iv) self-consistent calculations of two dimensional electron density in n-Al x Ga 1-x As/GaAs heterostructures and (v) a novel quantum well device “single quantum well transistor (SQWT)” proposed by the present authors. Experiments are performed in short n + n n + GaAs and very short channel MOSFETs. Analysis is made by using semiclassical treatment and Monte Carlo simulation. Self-consistent calculations are carried out on the two-dimensional electron gas formed in MOS inversion layers, n-Al x Ga 1-x As/GaAs heterostructures and Al x Ga 1-x As/GaAs/Al x Ga 1-x As single quantum well. Monte Carlo simulations of the two dimensional electrons in MOS inversion layers are found to explain the measured field dependence of the drift velocity. Self-consistent calculations provide design principle of HEMT and mechanisms of the new device SQWT. The present results indicate that the computer simulations are very helpful to investigate the physics of the nanometer structure devices and to develop new devices.
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