Abstract: A semiconductor device includes: a substrate having a base and an array of semiconductor pillars extending from the base, the substrate being formed with a plurality of trenches, each of which extends into the base and has two opposing trench side walls; a first insulative liner layer formed on each of the trench side walls of each of the trenches and divided into upper and lower segments by a gap that leaves a bit-forming surface of each of the trench side walls uncovered by the first insulative liner layer; and a plurality of buried bit lines, each of which extends into the base from the bit-forming surface of a respective one of the trench side walls of each of the trenches.

Abstract: A method for fabricating a vertical transistor comprises steps: forming a plurality of first trenches in a substrate; sequentially epitaxially growing a first polarity layer and a channel layer inside the first trenches, and forming a first retard layer on the channel layer; etching the first retard layer and the channel layer along the direction vertical to the first trenches to form a plurality of pillars; respectively forming a gate on a first sidewall and a second sidewall of each pillar; removing the first retard layer on the pillar; and epitaxially growing a second polarity layer on the pillar. The present invention is characterized by using an epitaxial method to form the first polarity layer, the channel layer and the second polarity layer and has the advantage of uniform ion concentration distribution. Therefore, the present invention can fabricate a high-quality vertical transistor.

Abstract: A semiconductor device includes: a substrate having a base and an array of semiconductor pillars extending from the base, the substrate being formed with a plurality of trenches, each of which extends into the base and has two opposing trench side walls; a first insulative liner layer formed on each of the trench side walls of each of the trenches and divided into upper and lower segments by a gap that leaves a bit-forming surface of each of the trench side walls uncovered by the first insulative liner layer; and a plurality of buried bit lines, each of which extends into the base from the bit-forming surface of a respective one of the trench side walls of each of the trenches.

Abstract: A method for fabricating a vertical transistor comprises steps: forming a plurality of first trenches in a substrate; sequentially epitaxially growing a first polarity layer and a channel layer inside the first trenches, and forming a first retard layer on the channel layer; etching the first retard layer and the channel layer along the direction vertical to the first trenches to form a plurality of pillars; respectively forming a gate on a first sidewall and a second sidewall of each pillar; removing the first retard layer on the pillar; and epitaxially growing a second polarity layer on the pillar. The present invention is characterized by using an epitaxial method to form the first polarity layer, the channel layer and the second polarity layer and has the advantage of uniform ion concentration distribution. Therefore, the present invention can fabricate a high-quality vertical transistor.

Abstract: A vertical transistor structure comprises a substrate, a plurality of pillars formed on the substrate and spaced from each other, a plurality of trenches each formed between two adjacent pillars, a protection layer formed on the surface of a first side wall and the surface of a second side wall of the trench, a first gate and a second gate respectively formed on the protection layer of the first side wall and the second side wall, and a separation layer covering a bottom wall of the trench. The present invention uses the separation layer functioning as an etch stopping layer to the first gate and the second gate while being etched. Further, thickness of the separation layer is used to control the distance between the bottom wall and the first and second gates and define widths of the drain and the source formed in the pillar via ion implantation.

Abstract: A self-aligned wet etching process comprises the steps of: etching a substrate having an etch protection layer on a surface thereof to form a plurality of trenches spaced from each other; and sequentially forming an insulating layer, an etch stop layer and a primary insulator in each trench, wherein the primary insulator is filled inside an accommodation space surrounded by the etch stop layer. During the wet etching process, the etch stop layer protects the primary insulator from being etched, whereby is achieved anisotropic wet etching. Further, the present invention expands the contact areas for electrically connecting with external circuits and exempts the electric contactors formed on the contact areas from short circuit caused by excessively etching the primary insulators.

Abstract: A self-aligned wet etching process comprises the steps of: etching a substrate having an etch protection layer on a surface thereof to form a plurality of trenches spaced from each other; and sequentially forming an insulating layer, an etch stop layer and a primary insulator in each trench, wherein the primary insulator is filled inside an accommodation space surrounded by the etch stop layer. During the wet etching process, the etch stop layer protects the primary insulator from being etched, whereby is achieved anisotropic wet etching. Further, the present invention expands the contact areas for electrically connecting with external circuits and exempts the electric contactors formed on the contact areas from short circuit caused by excessively etching the primary insulators.