Active-matrix nanocrystalline Si electron emitter array with a function of electronic aberration correction for massively parallel electron beam direct-write lithography: Electron emission and pattern transfer characteristics

Abstract

A planar nanocrystalline silicon (nc-Si) electron emitter array compatible with an active-matrix large-scale integrated (LSI) driving circuit has been developed for massively parallel electron beam direct-write lithography. The electron-emitting part of the device consists of a 50-μm-pitch and 200 × 200 arrays of nc-Si dots fabricated on a Si substrate, and via-first-processed through-silicon-via (TSV) plugs of poly-Si connected with the dots from behind the substrate. Tapered emitter-array etching and electrochemical-oxidation with subsequent annealing and super-critical rinsing and drying processes significantly enhanced the electron emission current by improving and stabilizing uniformity and reducing the process temperature. When the emitter array was driven, electrons were effectively injected into the nc-Si layer through the TSV plugs and quasiballistically emitted through the gold surface electrode. The nc-Si emitter responded to the input signal within times of 0.1 μs or less. A 1:1 pattern transfer experiment demonstrated that 5 × 5 subset square patterns selected from the emitter array can be reproduced on an e-beam resist without any distortions or fluctuations, showing that the energy dispersion of the emitted electrons is quite small. The basic concept of electronic aberration correction performed by an active-matrix LSI driving circuit is also discussed.