Kabushiki Kaisha Toshiba

Koichi Kishi

Soichi Sugiura

Yusuke Kohyama

Kazuyoshi Furukawa

Shizuo Sawada

Masanobu Ogino

Hiroyuki Noji

In a semiconductor memory device, a capacitor with a trench having a laterally expanded bottom part is provided, the area above the laterally expanded part being provided for a transistor and cell separation, this resulting in an increase in the degree of integration. This laterally expanded part is formed by etching a silicon oxide film which is sandwiched between a substrate and a silicon layer, and is obtained by forming a depression in a semiconductor substrate beforehand. A silicon layer or another semiconductor substrate is laminated by bonding to a semiconductor substrate such as this into which is formed a depression, a trench which extends to this depression being formed, and the required films being formed to obtain the desired trench capacitor. By forming an oxide film on all of or the depression part of the semiconductor substrate into which is formed the depression, it is possible to eliminate the influence of radiation, by improving insulation properties.

Semiconductor memory device and manufacturing method therefor

A semiconductor substrate according to the present invention includes a first semiconductor substrate of a first conductivity type, an insulating film selectively formed in the first semiconductor substrate to define an exposed surface region, and a second semiconductor substrate of a second conductivity type opposite to the first conductivity type being bonded to the first semiconductor substrate. A DRAM cell formed by using the semiconductor substrate includes a trench capacitor formed in the first semiconductor substrate through both the second semiconductor substrate and the exposed surface region, and a transfer transistor formed in the second semiconductor substrate.

Method of making a semiconductor memory device

According to this present invention, a semiconductor device includes source and drain diffusion layers, and a gate electrode formed on a substrate between the source diffusion layer and the drain diffusion layer. In addition, antioxidant films are respectively formed on the source diffusion layer and the drain diffusion layer. These antioxidant films are used for controlling a diffusion rate of an impurity contained in the source diffusion layer and the drain diffusion layer.

Semiconductor device having film for controlling diffusion of impurity

A p-type impurity diffusion layer is formed in a major surface region of an n-type silicon substrate. An insulating film is formed on the substrate, and a contact hole is formed in the insulating film at a position corresponding to the impurity diffusion layer. An n-type polysilicon layer is formed inside the contact hole. The p-type impurity diffusion layer and the n-type polysilicon layer constitute a diode. A p-n junction of the diode is formed on the major surface of the substrate or in the polysilicon layer above the major surface.

Growing community of inventors

Kawasaki, Japan

Koichi Kishi