Manufacture of variable capacity diode

Abstract

Abstract PURPOSE:To obtain ideal steep capacity change characteristics by a method wherein a concentration profile is formed in an extremely smooth curve by making up not less than threefold diffusion layers by means of an impurity diffusion method or an ion injecting method. CONSTITUTION:An N<-> epitaxial layer 2 to which P is added is stacked onto an N<+> type Si substrate 1 to which Sb is added, a hole is made to an SiO2 film 7, P is diffused at about decuple surface concentration of the N<-> layer 2, and an N<+> layer 3 is built up. P at concentration about three hundred times as much as the N<+> layer is diffused into the N<+> layer 3 to form an N<+> layer 4, and its thickness is made about 1.2mum. B ions are further injected to form a P<+> layer 5 in about 0.5mum thickness, concentration thereof is about thirty times as much as the N<+> layer 4, and a variable capacity diode is completed. According to this constitution, a concentration profile curve L is smoothed extremely, and a C-V characteristic is obtained which is rectilinear as compared to conventional devices.

Inventors

• 👤 Kaoru Nakagawa
• 👤 Tatsumi Tamura

Bibliographic Details