Semiconductor device

Abstract

Abstract PURPOSE:To prevent the erroneous operation of a semiconductor device by partly or completely surrounding a charge storage unit at the potential barrier which generates in the boundary between a P type Si substrate and a P<+> type layer to lower the efficiency of gathering electrons excited by alpha rays under the electrode. CONSTITUTION:B ions are implanted to a P type Si substrate 4, a P<+> type layer 3 is formed by providing the peak value of dosage in depth of 2,000-5,000Angstrom from the boundary between the substrate 4 and an oxidized film 2, and the density difference between the substrate and the layer 3 is set to 10<2>cm<-3> or higher. Then, a laser light is emitted to recover the crystallinity of the region in depth of 1,000-2,000Angstrom from the surface of the substrate 4. The energy of alpha rays in a package material is 9MeV or less, and the peak value of spectrum is approx. 4eV, its flight length is approx. 20mum, and electron and hole pairs are produced at the prescribed ratio along the track. The lifetime gamma (which is inversely proportional to the doping density of the layer 3) of recombination of the electrons 6 produced in the deep part from the layer 3 is short, and the electrons 6 are recombined with the holes in the layer 3 before flowing to the region 2. Further, the electrons are blocked at the potential barrier 8 in the boundary between the layers 3 and 4, the gathering efficiency to the electrode 1 is lowered, thereby preventing the erroneous operation due to inversion of stored information.

Inventors

• 👤 Masaaki Aoki
• 👤 正明 青木
• 👤 Kayao Takemoto
• 👤 一八男 竹本
• 👤 Toshiaki Masuhara
• 👤 増原　利明
• 👤 Seiji Kubo
• 👤 征治 久保
• 👤 Masanobu Miyao
• 👤 正信 宮尾
• 👤 Masao Tamura
• 👤 田村　誠男

Bibliographic Details