Peking University

Shiqiang Qin

Ru Huang

Poren Tang

Yimao Cai

Yu Jia Tang

Yue Pan

Xin Huang

Qianqian Huang

Gengyu Yang

Shenghu Tan

The present invention discloses a method for achieving four-bit storage by using a flash memory having a splitting trench gate. The flash memory with the splitting trench gate is disclosed in a Chinese patent No. 200710105964.2. At one side that each of two trenches is contacted with a channel, a programming for electrons is achieved by using a channel hot electron injection method; and at the other side that each of the two trenches is contacted with a source or a drain, a programming for electrons is achieved by using an FN injection method, so that a function of a four-bit storage of the device is achieved by changing a programming mode. Thus, a performance of the device is improved while a storage density is greatly increased.

Method for achieving four-bit storage using flash memory having splitting trench gate

The invention provides a flash memory array structure and a method for programming the same, which relates to a technical field of nonvolatile memories in ultra large scale integrated circuit fabrication technology. The flash memory array of the present invention includes memory cells, word lines and bit lines connected to the memory cells, wherein the word lines connected to control gates of the memory cells and the bit lines connected to drain terminals of the memory cells are not perpendicular to each other but cross each other at an angle; the control gates of two memory cells adjacent to each other along the channel direction between every two bit lines are controlled by two word lines, respectively, drain terminals thereof are controlled by two bit lines, respectively, and source terminals thereof are shared. The present invention also provides a method for programming the flash memory array structure, which can realize a programming with low power consumption.

Programming method for programming flash memory array structure

The present invention discloses a flash memory and the fabrication method and the operation method for the same. The flash memory comprises two memory cells of vertical channels, wherein a lightly-doped N type (or P type) silicon is used as a substrate; a P+ region (or an N+ region) is provided on each of the both ends of the silicon surface, and two channel regions perpendicular to the surface are provided therebetween; an N+ region (or a P+ region) shared by two channels is provided over the channels; a tunneling oxide layer, a polysilicon floating gate, a block oxide layer and a polysilicon control gate are provided sequentially on the outer sides of each channel from inside to outside; and the polysilicon floating gate and the polysilicon control gate are isolated from the P+ region by a sidewall oxide layer. The whole device is a two-bit TFET type flash memory with vertical channels which has better compatibility with prior-art standard CMOS process. As compared with a conventional MOSFET-based flash memory, the flash memory according to the present invention possesses various advantages such as high programming efficiency, low power consumption, effective inhibition of punch-through effect, and high density, etc.

Flash memory and fabrication method and operation method for the same

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Beijing, China

Shiqiang Qin