Title:
【発明の名称】不揮発性半導体メモリ装置
Document Type and Number:
Japanese Patent JP2786629
Kind Code:
B2
Abstract:
PURPOSE:To obtain an EPROM whose data retention characteristic has been enhanced by a method wherein an impurity concentration value of a source-drain diffusion layer of a memory cell constituting a NAND cell is set to be lower than that of a source-drain diffusion layer of a peripheral circuit in order to prevent destruction of a junction of the diffusion layer during a write operation and destruction of a gate insulating film. CONSTITUTION:Each plurality of rewritable memory cells where floating gates 4 and control gates 6 have been laminated on a semiconductor substrate 1 and a write operation and an erasure operation are executed by exchanging electric charge between the floating gate 4 and the substrate 1 by using a tunnel current have been respectively connected in series while source-drain diffusion layers 9 are used commonly, and constitute NAND cells; these are arranged in matrix form and constitute a memory array; An impurity concentration value of the source-drain layers 9 used commonly between the individual memory cells constituting said NAND cells is set to be lower than that of source-drain layers in a peripheral circuit. Said diffusion layers 9 are formed while ions of, e.g., phosphorus are implanted at an acceleration voltage of 40keV and a dose of 7X10<14>/cm<2>; a peak value of the impurity concentration value is set to be 10<20>/cm<3> or less.
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Inventors:
Ryozo Nakayama
Ryohei Kirizawa
Satoshi Inoue
Riichiro Shirata
Masaki Momomi
Yoshihisa Iwata
N. Ito
Chiba Masahiko
Masuoka Fujio
Ryohei Kirizawa
Satoshi Inoue
Riichiro Shirata
Masaki Momomi
Yoshihisa Iwata
N. Ito
Chiba Masahiko
Masuoka Fujio
Application Number:
JP29085787A
Publication Date:
August 13, 1998
Filing Date:
November 18, 1987
Export Citation:
Assignee:
Toshiba Corporation
International Classes:
G11C17/00; G11C16/04; H01L21/8246; H01L21/8247; H01L27/112; H01L27/115; H01L29/788; H01L29/792; (IPC1-7): H01L27/115; H01L21/8247; H01L29/788; H01L29/792
Domestic Patent References:
| JP60137068A | ||||
| JP61166154A | ||||
| JP6113668A |
Attorney, Agent or Firm:
Takehiko Suzue (2 outside)