INSTABILITY OF SINGLE-ELECTRON MEMORY AT LOW-TEMPERATURES IN AL ALOX/AL STRUCTURES/

A nanostructure based on a uniform one-dimensional array of ultrasmall tunnel junctions (a single-electron trap) characterized by an ability to maintain an excess charge of several electrons in an island is fab ricated and investigated. Changes in the state of the trap are detecte d by a single-electron transistor. At the working temperature T=35 mK the storage time of a charge state is more than 8 h (which is the dura tion of the experiment). It is demonstrated that the possible factors limiting the lifetime of a state at temperatures below the typical tem peratures for thermal activation include the influence of the random d istribution and drift of the effective background charges of the metal islands, as well as the reverse influence discovered here of the tran sistor on the trap. As the current passing through the transistor incr eases, the hysteresis loop in the dependence of the charge in the trap on the control voltage narrows. It is noted that an increase in the c urrent from 5 to 300 nA is equivalent to raising the working temperatu re to 250 mK. (C) 1997 American Institute of Physics.