Patent ID: 7474458

Claim:
A method for preparing a poled structure, comprising the steps of: forming a ferroelectric substrate with a first polarization direction and a first crystal structure, and the ferroelectric substrate having a top surface and a bottom surface; performing a doping process to form at least one inhibition block positioned in the ferroelectric substrate, and the inhibition block having a second crystal structure different from the first crystal structure; forming an electrode structure including a first electrode and a second electrode on the top surface and a third electrode on the bottom surface; and performing a poling process by applying a first voltage to the first electrode, a second voltage to the second electrode, and a third voltage to the third electrode so as to form a plurality of inverted domains in a portion of the ferroelectric substrate outside the inhibition block, wherein the first voltage is higher than the second voltage, the third voltage is higher than the second voltage, and the inverted domain have a second polarization direction from the first electrode to the second electrode.