Method of forming a vertically oriented device in an integrated circuit

Abstract

A system and method of forming an electrical connection ( ) to the interior of a deep trench ( ) in an integrated circuit utilizing a low-angle dopant implantation ( ) to create a self-aligned mask over the trench. The electrical connection preferably connects the interior plate ( ) of a trench capacitor to a terminal of a vertical trench transistor. The low-angle implantation process, in combination with a low-aspect ratio mask structure, generally enables the doping of only a portion of a material overlying or in the trench. The material may then be subjected to a process step, such as oxidation, with selectivity between the doped and undoped regions. Another process step, such as an etch process, may then be used to remove a portion of the material ( ) overlying or in the trench, leaving a self-aligned mask ( ) covering a portion of the trench, and the remainder of the trench exposed for further processing. Alternatively, an etch process alone, with selectivity between the doped and undoped regions, may be used to create the mask. The self-aligned mask then allows for the removal of selective portions of the materials in the trench so that a vertical trench transistor and a buried strap may be formed on only one side of the trench.