Sodium sensitive film field-effect sensor construction

摘要

A silicon-dioxide film is built on a silicon substrate. A silicon-nitride film is formed above this. On this film the sodium-alum-silicate membrane is deposited using reactive high-frequency magneton sputtering with a cylindrical cathode of sodium-alum-silicate glass at a power of 100-200 W in a 20/80% argon/oxygen atmos. at a pressure of 1 to 10 mu bar. This is followed by heat treatment at 400-600 deg C for 15-30 mins.. The cathode is formed by cold-pressing and sintering a powdered mixt. of 20 mol.% sodium oxide, 17 mol.% aluminium oxide ad 63 mol.% silicon oxide.