A voltage-programmable device in which the programming voltage V.sub.p and the "off" resistance R.sub.i are separately controlled. The device includes a body of semiconductor material having a doped region therein, and an amorphized layer in the doped region and abutting a surface, and a surface layer in the amorphized layer with the surface layer having a resistivity higher than the resistivity of the amorphized layer prior ot programming of the device. The surface layer has a miniscule thickness (on the order of 50-150 Angstroms) and does not affect the programming of the device. Moreover, the final resistance of the programmed device is not significantly affected by the presence of the first layer. The amorphized layer is formed by ion implantation, and the or by oxygen plasma treatment.