News Column

Patent Issued for Nonvolatile Semiconductor Storage Device

August 20, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- A patent by the inventors Ishihara, Takamitsu (Yokohama, JP); Muraoka, Koichi (Sagamihara, JP), filed on January 2, 2014, was published online on August 5, 2014, according to news reporting originating from Alexandria, Virginia, by VerticalNews correspondents.

Patent number 8796753 is assigned to Kabushiki Kaisha Toshiba (Minato-ku, JP).

The following quote was obtained by the news editors from the background information supplied by the inventors: "An aspect of the present invention relates to a nonvolatile semiconductor storage device and a method for manufacturing the same.

"NAND flash memory has a structure in which a plurality of nonvolatile semiconductor memory elements are connected in series. For example, a single element has a source region and a drain region formed on a surface of a semiconductor substrate, and a gate insulating film, a floating gate, an inter-gate insulating film, and a control gate that are sequentially stacked on a channel region sandwiched between the source region and the drain region. In a miniaturization of a nonvolatile semiconductor memory element using a floating gate, there are pointed out that it is difficult to reduce the height of the floating gate, that it is difficult to perform ion implantation for forming a diffusion layer or a channel, and that interference between transistors occur."

In addition to the background information obtained for this patent, VerticalNews journalists also obtained the inventors' summary information for this patent: "According to an aspect of the present invention, there is provided a nonvolatile semiconductor storage device including: a semiconductor substrate; a source region and a drain region that are formed in the semiconductor substrate so as to be separated from each other and so as to define a channel region therebetween; a tunnel insulating film that is formed on the channel region; an insulative charge storage film that is formed on the tunnel insulating film; a conductive charge storage film that is formed on the insulative charge storage film so as to be shorter than the insulative charge storage film in a channel direction; an interlayer insulating film that is formed on the conductive charge storage film; and a gate electrode that is formed on the interlayer insulating film.

"According to another aspect of the present invention, there is provided a nonvolatile semiconductor storage device including: a semiconductor substrate; a source region and a drain region that are formed in the semiconductor substrate so as to be separated from each other and so as to define a channel region therebetween; and a laminated structure including: a tunnel insulating film that is formed on the channel region; an insulative charge storage film that is formed on the tunnel insulating film; a conductive charge storage film that is formed on the insulative charge storage film;

"an interlayer insulating film that is formed on the conductive charge storage film; and a gate electrode that is formed on the interlayer insulating film, wherein the laminated structure is formed so that a width thereof becomes narrow continuously from the gate electrode toward the tunnel insulating film in a channel direction.

"According to still another aspect of the present invention, there is provided a method for manufacturing a nonvolatile semiconductor storage device, the method including: sequentially forming, on a semiconductor substrate, a tunnel insulating film, an insulative charge storage film, a conductive charge storage film, an interlayer insulating film, and a gate electrode; patterning, at least, the tunnel insulating film, the insulative charge storage film, and the conductive charge storage film; forming a source region and a drain region in the semiconductor substrate; and processing the conductive charge storage film so as to be shorter than the insulative charge storage film in a channel direction."

URL and more information on this patent, see: Ishihara, Takamitsu; Muraoka, Koichi. Nonvolatile Semiconductor Storage Device. U.S. Patent Number 8796753, filed January 2, 2014, and published online on August 5, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8796753.PN.&OS=PN/8796753RS=PN/8796753

Keywords for this news article include: Electronics, Semiconductor, Kabushiki Kaisha Toshiba.

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Source: Electronics Newsweekly


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