Fabrication of one-dimensional GaAs channel-coupled InAs quantum dot memory device by selective-area metal-organic vapor phase epitaxy

Abstract

Narrow wirelike openings were defined on SiO2-masked GaAs (001) substrates by electron-beam lithography and wet chemical etching methods. A one-dimensional GaAs channel-coupled InAs quantum dot memory device was fabricated in this opened area by the selective-area metal-organic vapor phase epitaxy. Drain current measurement by sweeping the gate voltage forward and backward showed clear hysteresis up to 180K due to electrons charging into the quantum dots with a threshold voltage difference (ΔVth) of 165mV at 20K and 29mV at 180K. Comparison of experimental ΔVth values with the theoretically calculated ones showed that around 300 and 50 electrons were responsible for the memory operation at 20 and 180K, respectively. Real time measurements showed that the write/erase states of the memory device were discriminated for more than 5min at 20K and about 100s at 77K.