Abstract: Disclosed is a process fo fabrication of a MESFET in which starting with a GaAs substrate having a shallow N- layer covered with nitride, a submicron-wide dummy gate mask consisting of upper and lower portions made of dissimilar materials is formed. Multilayer organic and sidewall image transfer techniques are employed for forming the mask. The nitride is etched using the gate mask. N+ source/drain are formed by ion implantation. The lower portion of the gate mask is etched to expose the periphery of the nitride. Refractory metal for source/drain contacts is deposited. An oxide laeyr is deposited to passivate the source/drain contacts and to fully cover the exposed nitride periphery. The gate mask is removed. High temperature anneal is accomplished to simultaneously activate the N+ regions and anneal the contact metal. By RIE the exposed nitride removed leaving submicron spacers thereof. Gate metal is deposited in the gate region.

Abstract: A balanced photoconductor usage control system for an electrophotographic copier/printer machine having a photoconductor containing thereon two page images areas, is employed to solve the problem of excessively high background level due to toner filming. More specifically, the control system includes memory means for retaining a location of a last page image area which was last used to produce a page, and control means jointly responsive to a presence of a full page condition in a page buffer, and to the memory means to effect production of a next page on an alternate page image area.