Non-volatile semiconductor memory device and method for manufacturing the same
DCFirst Claim
1. An EEPROM semiconductor memory device comprising:
- a semiconductor substrate having a first conductivity type, said semiconductor substrate being divided into a cell array region and a peripheral circuit region;
a first impurity-doped region having said first conductivity type formed in a first surface portion of said semiconductor substrate in said cell array region;
a second impurity-doped region having a second conductivity type formed in said first surface portion of said semiconductor substrate in said cell array region, said second impurity-doped region enclosing said first impurity-doped region;
a memory cell comprising;
a memory source region and a memory drain region formed on a surface portion of said first impurity-doped region, anda floating electrode formed on said first impurity-doped region and a control electrode formed on said floating electrode;
a third impurity-doped region having said first conductivity type formed in a first surface portion in said peripheral circuit region of said semiconductor substrate;
a first MOS transistor comprising;
first source and drain regions formed in respective surface portions of said third impurity-doped region, anda first gate electrode formed on said third impurity-doped region;
a second MOS transistor comprising;
second source and drain regions formed directly in respective second surface portions in said peripheral circuit region of said semiconductor substrate, anda second gate electrode formed on said semiconductor substrate;
a fourth impurity-doped region having said second conductivity type and being formed in a third surface portion in said peripheral circuit region of said semiconductor substrate; and
a third MOS transistor comprising;
third source and drain regions formed in respective surface portions of said fourth impurity-doped region, anda third gate electrode formed on said fourth impurity-doped region.
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Abstract
An EEPROM device in which a high voltage is applied to the chip during the memory cell operation and a method for the manufacturing the same are disclosed. On a P-type semiconductor substrate, a first N-well is formed in a surface portion of the substrate in the cell array region and a second N-well is formed in a first surface of the substrate in the peripheral circuit region. An EEPROM memory cell is formed on the first P-well and a first NMOS transistor is formed on the second P-well. Also, a second NMOS transistor is formed on a second surface portion of the semiconductor substrate in the peripheral circuit 10 region and a PMOS transistor is formed on the second N-well. The impurity concentrations of the first and second P-wells are controlled in accordance with the characteristic of the MOS transistors to be formed. Further, a second NMOS transistor having a resistance against a high voltage is directly formed on the P-type substrate. Thus, the electric characteristic of the EEPROM device is enhanced.
73 Citations
9 Claims
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1. An EEPROM semiconductor memory device comprising:
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a semiconductor substrate having a first conductivity type, said semiconductor substrate being divided into a cell array region and a peripheral circuit region; a first impurity-doped region having said first conductivity type formed in a first surface portion of said semiconductor substrate in said cell array region; a second impurity-doped region having a second conductivity type formed in said first surface portion of said semiconductor substrate in said cell array region, said second impurity-doped region enclosing said first impurity-doped region; a memory cell comprising; a memory source region and a memory drain region formed on a surface portion of said first impurity-doped region, and a floating electrode formed on said first impurity-doped region and a control electrode formed on said floating electrode; a third impurity-doped region having said first conductivity type formed in a first surface portion in said peripheral circuit region of said semiconductor substrate; a first MOS transistor comprising; first source and drain regions formed in respective surface portions of said third impurity-doped region, and a first gate electrode formed on said third impurity-doped region;
a second MOS transistor comprising;second source and drain regions formed directly in respective second surface portions in said peripheral circuit region of said semiconductor substrate, and a second gate electrode formed on said semiconductor substrate; a fourth impurity-doped region having said second conductivity type and being formed in a third surface portion in said peripheral circuit region of said semiconductor substrate; and a third MOS transistor comprising; third source and drain regions formed in respective surface portions of said fourth impurity-doped region, and a third gate electrode formed on said fourth impurity-doped region. - View Dependent Claims (2, 3, 4, 5, 6, 9)
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7. An EEPROM semiconductor memory device comprising:
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a P-type semiconductor substrate which is divided into a cell array region and a peripheral circuit region; a first P-well formed in a surface portion in said cell array region of said semiconductor substrate; a first N-well formed in said surface portion in said cell array region of said semiconductor substrate, said first N-well enclosing said first P-well; a memory cell comprising; a memory source region and a memory drain region formed on a surface portion of said first P-well, a floating electrode formed on said first P-well, and a control electrode formed over said floating electrode; a second P-well formed in a first surface portion of said peripheral circuit region of said semiconductor substrate; a first NMOS transistor comprising; first source and drain regions formed in respective surface portions of said second P-well, and a first gate electrode formed on said second P-well; a second NMOS transistor comprising; second source and drain regions formed directly in a second surface portion of said peripheral circuit region of said semiconductor substrate, and a second gate electrode formed on said second surface portion of said peripheral circuit region of said semiconductor substrate; a second N-well formed in a third surface portion of said peripheral circuit region of said semiconductor substrate; and a PMOS transistor comprising; third source and drain regions formed in a surface portion of said second N-well, and a third gate electrode formed on said second N-well. - View Dependent Claims (8)
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Specification