Nec Corporation

Nobuhiro Tanabe

Yoshihiro Hayashi

Tsuneo Takeuchi

Kazushi Amanuma

Shinobu Saito

A semiconductor memory device is provided, which prevents the characteristic of storage capacitors from degrading without chip-area increase of memory cells. Each of storage capacitors has a dielectric sandwiched by lower and upper electrodes. The lower electrodes are formed by a patterned, common electrically-conductive layer. The dielectrics are formed by a patterned, common ferroelectric layer formed on the common electrically-conductive layer which is entirely overlapped with the common electrically-conductive layer. The upper electrodes are regularly arranged on the common ferroelectric layer and are located outside the rows and columns of a matrix array where the windows of the common electrically-conductive layer and common ferroelectric layer are aligned. Wiring lines are formed over the upper electrodes through an interlayer insulating layer covering the storage capacitors, thereby electrically connecting the upper electrodes and select transistors.

Semiconductor memory device having an array of memory cells including a select transistor and a storage capacitor wiring lines at 45&deg; angles

In a method of manufacturing a semiconductor device, a CMOS section composed of an N-channel MOS transistor and a P-channel MOS transistor and a memory section composed of at least a transfer gate MOS transistor is formed on a substrate. A plurality of conductive plugs is formed to penetrate a laminate insulating film to the MOS transistors. The laminate insulating film is composed of a first insulating film and a second insulating film. A capacitor section is formed on the laminate insulating film and the capacitor section is composed of an upper electrode, a dielectric film and a lower electrode. A third insulating film is formed on the laminate insulating film and the capacitor section. A wiring pattern is formed on the third insulating film to partially penetrate the second insulating film connect to the plurality of conductive plugs. A wiring pattern may be disposed in the laminate insulating film to connect at least two of the plurality of conductive plugs.

Semiconductor device with conductive plugs

In a ferroelectric memory, a malfunction in which data are reversed at the time of writing after reading out of data is prevented. Using a transistor to short-circuit two common lines which are connected to a memory element, the two common lines are short-circuited at the preparing stage for writing new data, and thereby such a malfunction which occurs reversal of data owing to an electric potential difference between common lines is prevented.

Ferroelectric memory and writing method of therein

A plurality of word lines extend linearly and parallel to each other. A reference word line is positioned to divide the word lines into two groups of word lines. A plurality of bit lines are folded on the reference word line symmetrically with respect to the reference word line and spaced at intervals from each other. Each of memory elements comprises a capacitive element and a switching transistor having a source connected to the capacitive element, a drain connected to one of the bit lines, and a gate connected to one of the word lines. The memory elements are disposed in a matrix such that they are spaced across and along the word lines and paired memory elements whose switching transistors have drains connected to the same bit line are positioned symmetrically with respect to the reference word line.

Growing community of inventors

Tokyo, Japan

Nobuhiro Tanabe