FACTORS AFFECTING RESOLUTION IN SCANNING ELECTRON-BEAM-INDUCED PATTERNING OF SURFACE-ADSORPTION LAYERS

The monoatomic hydride layer on silicon was used as a prototype for re sistless electron beam lithography. Arbitrary patterns with linewidths below 60 nm have been achieved. The variation of the linewidth with e lectron energy, electron dose, and substrate thickness was studied to determine the mechanisms that govern surface hydrogen desorption and s ubsequent pattern formation. Unlike in resist based lithography, no re solution enhancement was observed with decreasing substrate thickness. The experimental data in combination with Monte Carlo simulations of the backscattered and transmitted electrons suggest that surface hydro gen desorption and pattern formation are not strongly related to the b ackscattered electrons and the secondary electrons (energies < 50 eV) associated with the backscattered electrons. (C) 1998 American Institu te of Physics.