Mitsubishi Denki Kabushiki Kaisha

Nobuaki Andoh

Shinichi Kobayashi

Kenji Noguchi

Kenji Kohda

Tsuyoshi Toyama

Osamu Ueda

In a nonvolatile semiconductor device in which source metal interconnections for coupling to ground a source of a floating gate type memory transistor are commonly provided for each predetermined plurality of memory transistors, switching transistors are provided for each column for coupling to ground columns excluding the selected column when a single column is selected in response to an external column address. Each of the switching transistors operates in response to an inverted signal of an output of a column decoder. According to this structure, a variation in source potential of each memory transistor caused by the difference in source resistance associated with each of the memory transistors is reduced.

Nonvolatile semiconductor memory device with reduced variation in source

A non-volatile semiconductor memory device includes a substrate (1) having a plurality of element-forming regions (3), a plurality of recesses (32) located between the element-forming regions (3), and a plurality of element-isolating regions (31); word lines (8a to 8d); bit lines (10) orthogonal to this word lines; and memory cells (511) each formed at the point of intersection of these word and bit lines at each element-forming region (3). Each memory cell (511) includes an electrically floating electrode (5) in the form of a flat plate, a control gate electrode (7) in the form of a substantially flat plate formed on the floating gate electrode (5) and connected to the word lines (8a to 8d), and a pair of impurity regions (21, 23) formed respectively at opposite sides of the floating gate electrode (5) on the surface of a semiconductor substrate (1). An element-isolating region (31) includes an element-isolating electrode layer (30) formed on the surface of the semiconductor substrate (1) and in the recesses (32).

Electronic integrated circuit having an electrode layer for element

An EPROM as a nonvolatile semiconductor memory device includes a semiconductor substrate 1, a gate oxide layer 3 formed on the surface of the semiconductor substrate 1, a plurality of floating gates 4a and 4b formed on the gate oxide layer 3 so as to overlap one another at the portions 4ab thereof with a gate oxide layer 14 sandwiched between the overlapping portions 4ab, and control gate strips 5 formed on a gate oxide layer 6 which overlies the floating gates 4a and 4b.

Floating gate type semiconductor memory device

An EEPROM having an ECC circuit further comprises a counter circuit. The ECC circuit checks and corrects bit errors included in data read out from a memory cell array. In addition, the ECC circuit generates a predetermined signal every time it corrects a bit error. The counter circuit counts a predetermined signal generated from the ECC circuit.

Semiconductor memory device with error check and correcting function

Memory transistors are arranged in a plurality of rows and a plurality of columns. A source line is formed for every two bit lines formed in the column direction, each connected to the memory transistors of one column. A source region of each memory transistor is connected, on one side, to a source line adjacent thereto and, on the other side, to a source line through the source region of the adjacent memory transistor, through impurity regions respectively. A floating gate is formed to extend to a position under the corresponding source line. In another example, a source line is formed for each bit line formed in the column direction. The source region of each memory transistor is connected to the adjacent source lines on both sides thereof through impurity regions. The floating gate is formed to extend to positions under both adjacent source lines.

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Hyogo, Japan

Nobuaki Andoh