Scanning probe lithography using a cantilever with integrated transistor for on-chip control of the exposing current

Abstract

Scanning probe lithography uses electrons field emitted from a micromachined probe tip to expose organic polymer resists. The exposed pattern dimension is set by the electron dose delivered to the resist and can be controlled down to <30 nm. We have integrated a metal–oxide–semiconductor field-effect transistor (MOSFET) onto the cantilever chip to act as a current source to control the electron exposure dose from the tip. The silicon cantilever and tip form the drain of the MOSFET. In the saturation regime, the transistor acts as a voltage-controlled current source. A low voltage signal to the transistor gate sets the exposure dose. We describe the design and fabrication of this device and demonstrate that the integrated transistor can be used as the sole current-control electronics for uniform high-resolution lithography, eliminating the need for external circuitry.