Mesoscopic Devices Using InAs Heterostructures and Their Applications

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With the advent of microelectronics, the device size and its physical phenomena have reached to the mesoscopic region. There have been strong effort on mesoscopic physics and device applications mostly based on GaAs operated at cryogenic temperatures. We have investigated mesoscopic devices based on InAs heterostructures in order to realize quantum effect devices operated at higher temperatures. First of all, we have investigated fabrication method of quantunm dot structures for the purpose of device applications. Strained InAs heterostructure was shown to inherit inhomogeneous strain distribution which strongly affects its energyband inhomogeniety. Self-assembled InAs dots were shown to distribute regularly on patterned GaAs substrates. Secondly, we have succeeded in fabricating split-gate HEMT structure with InAs dots and observed single electron charging of the dot at up to 40K.We have also succeeded in fabricating InAs wuantum wires and observed quantized conductance at 80K.Thirdly, high performance InAs channel FETs have been fabricated by Platinum gate structure and P' gate structure based on InP.We have successfully applied InAs channel FET structure to superconducting weak links and obtaind IcRn product of 2meV.Finally, InAs heterostructures were also applied to resonat tunneling structures : energy spectra of ballistic electrons were measued by using InAs/AlSb RTD and up to seven phonon replicas were observed at 77K.RTD with InAs well and InGaAs pre-well has been shown to have almost doubled peak current. GaAs/AlGaAs RTD with InAs dots buried in cathode GaAs adjacent to the barrier has been shown to have memory effect due to the charging of InAs dots and charged electrons were shown to be dischraged by resonant tunneling. The clear hysteresis were observed at room temperature.