DE1489258

1,094,068. Semi-conductor devices. RADIO CORPORATION OF AMERICA. Dec. 7, 1964 [Dec. 26, 1963], No. 49763/64. Heading H1K. A crystalline Si body of p, n or i conductivity type covered in part by a silicon oxide coating has a thin layer of n, n+ or n conductivity type respectively immediately below the coating, of resistivity 3-100 K# per square. A p-type Si wafer 10, is coated with a silicon dioxide layer 20 by heating in dry O 2 , and then forming the thin layer 22 by heating at 500‹ C. for 50 minutes in a mixture of N 2 + H 2 . If the oxide layer is formed by heating in water vapour then the inversion layer is removed by heating in vacuo, O 2 , N 2 or Ar prior to the formation of the thin layer. An insulated gate field-effect transistor may be made.