Buried-strap formation in a dram trench capacitor

摘要

A method for making an electrical connection between a trench storage capacitor and an access transistor in a DRAM cell. The electrical connection is formed through the selectively controlled outdiffusion of either N-type or P-type dopants present in the trench through a single crystalline semiconducting material which is grown by epitaxy (epi) from the trench sidewall. This epitaxially grown single crystalline layer acts as a barrier to excessive dopant outdiffusion which can occur in the processing of conventional DRAMs.