Semiconductor fabrication process using sacrificial oxidation to reduce tunnel formation during tungsten deposition

摘要

A method of fabricating a CMOS-type structure entails forming a pair of conductive portions (68 and 70) on a pair of dielectric portions (72 and 74) lying on monocrystalline silicon (60). N-type dopant-containing ions are implanted into the silicon to form a pair of doped regions (78/82) separated by p-type material under one of the dielectric portions. Boron dopant-containing ions are similarly implanted to form a pair of doped regions (84) separated by n-type material under the other dielectric portion. A sacrificial oxidation is performed by oxidizing surface material of each conductive portion and each doped region and then removing at least part of the so oxidized material (86) down to the underlying silicon. Tungsten (88 and 90) is deposited on the exposed silicon after which a patterned electrical conductor is provided over the tungsten. Use of the sacrificial oxidation substantially reduces tunnel formation during the tungsten deposition.