Abstract: An upper part of a SIC substrate 1 is oxidized at a temperature of 800 to 1400° C., inclusive, in an oxygen atmosphere at 1.4×102 Pa or less, thereby forming a first insulating film 2 which is a thermal oxide film of 20 nm or less in thickness. Thereafter, annealing is performed, and then a first cap layer 3, which is a nitride film of about 5 nm in thickness, is formed thereon by CVD. A second insulating film 4, which is an oxide film of about 130 nm in thickness, is deposited thereon by CVD. A second cap layer 5, which is a nitride film of about 10 nm in thickness, is formed thereon. In this manner, a gate insulating film 6 made of the first insulating film 2 through the second cap layer 5 is formed, thus obtaining a low-loss highly-reliable semiconductor device.

Abstract: A process for producing a perovskite-type oxide of the ABO.sub.3 type is disclosed. A solution of an element A (Pb, Ca, Sr and/or La) and an element B (Ti and/or Zr) is brought into contact with oxalic acid in the presence of an alcohol to precipitate oxalic acid salts; the acid radicals in the solution are neutralized with an amine or ammonia; the resulting precipitate is then subjected to calcination.A fine-grained ferroelectric oxide having a sharp grain size distribution can be produced, with its chemcial composition being exactly controlled. This oxide is suitable for use as a piezoelectric, pyroelectric or ferroelectric material.