The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 25, 1995
Filed:
Jan. 16, 1992
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A semiconductor device having superior electrical characteristics is fabricated. 50 nm of the surface of a CZ (100) silicon substrate is oxidized to form an oxidized film. Afterwards a first ion implantation of boron ions is conducted to this silicon substrate amounting to 7.times.10.sup.13 cm.sup.-2 with acceleration energy of 1.5 MeV. Next, a first annealing in nitrogen ambient at 1050.degree. C. for 40 minutes is conducted. Through this ion implantation process a damaged layer and a dopant layer are formed within the silicon substrate. Boron ions are implanted as a second ion implantation, with a dosage of 7.times.10.sup.13 cm.sup.-2, followed by a second implanted annealing in nitrogen ambient at 1050.degree. C. for 40 minutes. Further, as a third ion implantation, boron ions are implanted with a dosage of 6.times.10.sup.13 cm.sup.-2 followed by a third annealing in nitrogen ambient at 1050.degree. C. for 40 minutes. In the dopant layer thus formed, through a plurality of repeated high energy ion implantation and subsequent annealing, in order to obtain the desired dopant concentration, density of secondary defect occurrences may be lowered.