Patterned ferroelectric domains and domain selective etching of the patterned domains can provide ferroelectrics-based photonic crystals. In this paper, electron-beam has been applied to switch domains in LiNbO3 (LN) and LiTaO3 (LT) crystals. The complex dynamics of interaction of beam electrons with the crystals has been highlighted. Based on this research, an improved e-beam domain patterning technique utilizing resist covering is successfully applied to switch domains in a z-cut 1 mol% MgO-doped stoichiometric LN at room temperature. (c) 2006 Elsevier B.V. All rights reserved.