United Microelectronics Corp.

Nai-Jen Yeh

Sheng-Hsing Yang

Cheng-Chih Kung

Yu-Chih Chuang

Che-Pin Tseng

Although the spacers are formed on the sidewalls of gate electrode and words lines via the same steps of deposition and etch-back processes, only the spacers disposed at the sidewalls of the gate electrode are practical for fabricating peripheral devices with LDD structure, and such fabrication is impractical in the memory cell region. On the contrary, the region beneath the spacers disposed at the sidewalls of word lines will become the path through which leakage current flows. The present invention makes use a shielding layer to cover the second active region as a masking, and then removes the spacers disposed at the sidewalls of word lines. Afterwards, isolating regions are formed through one implantation procedure to thereby decrease leakage current and simplify the process flow.

Method for fabricating isolating regions for buried conductors

A method of fabrication of an semiconductor device comprises applying an impurity of a predetermined polarity to a silicon substrate; forming a well by applying an impurity of an opposite polarity to a region in the silicon substrate; forming a first masking layer on the surface of the substrate; providing openings in the masking layer and implanting dopant ions of a first polarity into the surface of the substrate in a set of first regions selected in the substrate and the well forming a second masking layer on the surface of the substrate; implanting dopant ions of a second polarity through a second mask in other regions selected in the well and the substrate; removal of the second masking layer; formation of field oxide structures over the first and second regions; forming gate oxide layers above the exposed portions of the first and second central regions; and formation of conductive gate structures over the gate oxide layers.

Growing community of inventors

Hsin Chu County, Taiwan

Nai-Jen Yeh