METHOD FOR FORMING MOSFET DEVICE HAVING DIFFERENT THICKNESS OF GATE INSULATING LAYER

摘要

PURPOSE: A method for forming a metallic oxide semiconductor field effect transistor is provided to prevent damage to a channel epitaxial layer by forming a nitrogen injecting layer in a first area and a second area of a semiconductor substrate with uniform concentration. CONSTITUTION: A first area(AR1) and a second area(AR2) are included on a semiconductor substrate. An oxide film of a first thickness is formed on the semiconductor substrate. A nitrogen injecting layer(108) of uniform concentration is formed on the semiconductor substrate of the first area and the second area. The oxide film is changed into a nitride oxide film(107) in the semiconductor substrate in which the nitrogen injecting layer is formed. An insulating layer(110a) of second thickness is formed on the nitride oxide film of the first area and the nitrogen injecting layer of the second area.