Recent improvements in the integration of field emitters into scanning probe microscopy sensors

Recent improvements in the fabrication of integrated field emitters with a control electrode into scanning probe microscopy sensors are presented and discussed. Compared to earlier work the precursor material for the electron beam induced deposition of the emitter was changed from a Pt precursor ((CH3C5H4)Pt(CH3)(3)) to a C precursor (C14H10) which leads to a higher process yield and an improved process stability. The change of the material for the control electrode from Pt to Cr results in better compatibility to standard semiconductor processing. The field emitter devices were fabricated by focused charged particle beam processing revealing emission currents of 0.8 mu A/tip for gate voltages of about 65 V. Possible reasons for the high turn-on voltages V-to were investigated by high resolution transmission electron microscopy combined with EDX analyses and approaches for reducing V-to are presented. (C) 2008 Elsevier B.V. All rights reserved.