We have calculated the effect that classical potential fluctuations caused by the random positions of donors have on the characteristics of a narrow modulation-doped field-effect transistor with a short gate. The threshold becomes noisy, irreproducible from device to device, and is broadened to over 200 mV. Its form is in good agreement with the recent experiments of Washburn et al. [Phys. Rev. B 38, 1554 (1988)]. Such fluctuations in potential will limit the performance of submicrometer field-effect transistors. Narrow "quantum wires" formed in semiconductor heterolayers are likely to be even more susceptible to these fluctuations because of the poor electronic screening.

• Received 30 June 1988

DOI:https://doi.org/10.1103/PhysRevB.39.3423