| http://www.w3.org/ns/prov#value | - As shown in FIG. 12A, a P-type silicon substrate 141 (crystal orientation<111) whose impurity concentration lies in a range of from 1???1016 to 1???1017 cm-2 order is prepared and an area other than a portion which serves as an element forming region 122 is removed by a depth of about 150 nm by the etching process to thereby form a stepped portion 142.
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