39 in fig1 f the third titanium oxide region 34 had a sheet resistance of 100 kilohms per square which was less than that of the second titanium oxide region 26 the fabrication of the schottky diode 10 was now completed we have illustrated the completed schottky diode 10 in a plan view in fig2 as will be noted from both fig1 f and 2 the third titanium oxide region 34 contacts the barrier electrode 36 constituted of the unoxidized titanium layer 18 34 and the aluminum layer 20 34 it will also be observed from fig2 that the third titanium oxide region 34 is of annular shape as seen in a plan view as in this figure surrounding the barrier electrode 36 thus the third titanium oxide region 34 overlies the second titanium oxide region 26 which also is annular in shape via the silicon oxide layer 28 the unoxidized titanium layer 30 39 and the aluminum layer 32 constitute in combination an anode 38 the annular peripheral part of the first titanium oxide region 24 which was left uncovered by the silicon oxide layer 28 was oxidized during the heat treatment for the oxidation of the titanium layer 30 consequently the sheet resistance of this peripheral part of the first titanium oxide region 24 is higher than 50 000 megohms per square in the schottky diode 10 fabricated as above both second titanium oxide region 26 and third titanium oxide region 34 constitute field plates it is the second titanium oxide region 26 which also serves as resp that contributes to the enhancement of its voltage blocking capability when the diode is reverse biased with the cathode 22 positive and the anode 38 negative for the following reason the reverse voltage impressed to the.