OPTIMIZATION OF ISLAND SIZE IN SINGLE-ELECTRON TUNNELING DEVICES - EXPERIMENT AND THEORY

We have investigated the influence of island size on the operation of single electron tunneling (SET) devices. The self-heating, self-capaci tance, and charge noise have been determined for six SET transistors w ith island sizes varying from 0.17X0.17 mu m(2) to 5X5 mu m(2). The I- V characteristics of these devices can be well fit to a model where th e heat how from the device is limited by the electron-phonon coupling. The best fit to this model was obtained with an electron-phonon coupl ing parameter of Sigma=0.3X10(9) W K-5 m(-3). We have found a clear in dication that the charge noise of our SET transistors, which are fabri cated with the usual techniques, increases with increasing island size . These results have been used to estimate the thermal error of a sing le electron turnstile assuming that self-heating and charge noise in t he turnstile are the same as in our SET transistors. The accuracy of t he turnstile is dramatically reduced by the self-heating and the charg e noise. (C) 1995 American Institute of Physics.