MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PURPOSE:To decrease the number of patterns is such a way that only a single layer of a nitride film is used, and to make it possible to use metals having high fusing points as the material of the patterns, by forming patterns by a lift-off method by the use of an opening whose side surfaces is inversely tapered due to an etching rate difference in the direction of thickness which is produced by selective etching for a nitride film that is deposited by a CVD method while varying the temperature. CONSTITUTION:Source and drain electrodes 13 and 14 are formed on a GaAs operative layer 12 which is formed on a semiconductor substrate 11. And a Plasma-enhanced CVD (P-CVD) nitride film 15 is formed on the surface of the substrate with a CVD unit while increasing a depositing temperature. Then, a resist 16 is coated on the surface of the P-CVD nitride film 15 to perform patterning and a selective etching is carried out after providing an opening. In such a case, side surfaces of the etching opening is inversely tapered due to an etching rate difference of the nitride film 15 because of difference in the depositing temperature. The resist 16 is removed to carry out recess etching, and a gate metal 17 is deposited. A lift-off process is performed at the peripheral ends of opening of the nitride film 15. Then, after the nitride film 15 as well as a gate metal 17 that is deposited on the nitride film 15 are removed, gate electrodes are formed.