POROUS ALPHA FERRIC OXIDE THIN FILM USED AS GAS SENSOR BY PECVD METHOD

摘要

PURPOSE: A porous alpha-Fe2O3 thin film used as a gas sensor by PECVD(plasma enhanced chemical vapor deposition) method is provided to make the particle size of alpha-Fe2O3 film and more porous, and to enhance the gas sensitivity. CONSTITUTION: In a PECVD(plasma enhanced chemical vapor deposition) method, the rough alumina or a polished alumina substrate is inserted in the chamber after ultrasonic cleaning process by using methanol, and the cleaning process of the inserted substrate is formed by using argon or nitrogen gas for 20 minutes. Subsequently the plasma etching process of the substrate is carried by using only argon gas. Wherein alpha-Fe2O3 is formed by bubbling Fe(CO)5 and by using the argon gas as carrier gas and is injected into the chamber after reacting with oxide in a mixing tank. The flux of gas is controlled MFC(mass flow controller) and the thin film is deposited by producing plasma in the chamber and thermal process follows subsequently.