JPS6473675A - Manufacture of mis-type semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To realize high integration by a method wherein a thin conductor layer is formed on a whole face of a semiconductor substrate prior to a high-dose ion implantation operation and an ion is implanted through the conductor layer. CONSTITUTION:Prior to an implantation operation of ions of arsenic a thin conductive film 15 is first formed on a whole face. A thickness of the conductive layer 15 must be thin to the extent that an implantation of the ion into a substrate is not suppressed. For this, e.g. about 50-200Angstrom of aluminum is deposited by a sputtering method. After that, the ion of arsenic is implanted at an energy of 70kev and an implantation quantity of about 5X10<15>ions/cm<2>; a source region and a drain region 16a, 16b are formed. During this process, the ion is implanted through the conductive layer 15 and a gate oxide film 13. Because the conductor layer 15 exists, an electric charge generated on its surface during the ion implantation flows out to the outside of a semiconductor substrate through the conductor layer and is not accumulated on the surface of a device; accordingly, insulation of the gate oxide film 13 is not broken down due to to a high electric field. After the ion implantation operation, the conductive layer is removed from the whole face by a wet etching operation or the like.