Electrical properties of the silicon oxide/Si structure formed with perchloric acid at 203 degrees C

Immersion of Si in perchloric acid (HClO4) at 203 degreesC forms silicon di oxide (SiO2) layers with a low interface state density of 1.5 x 10(10) cm(2 ) eV(-1) even without hydrogen treatment. The SiO2 thickness increases line arly with the immersion time, and a 25 nm-thick SiO2 layer is formed by the immersion for 400 min. The leakage current density for the as-prepared oxi de layers is high, while after heat treatment at 900 degreesC in nitrogen, it decreases to less than 10(-9) A cm(-2) at the gate bias of ii V. This de crease is attributable to the desorption of chlorine-containing species fro m the SiO2 layers. (C) 2001 Elsevier Science Ltd. All rights reserved.