Siemens Corporation

Siemens Microelectronics Limited

Guenther Koffler

Paul Wensley

Siegfried Mischitz

Known methods for forming trench storage capacitors require the chemical vapour deposition (CVD) of an undoped silicon oxide layer in order to prevent auto doping of side wall of a semiconductor trench. This layer is deposited once an arsenic doped silicon oxide layer has been disposed and etched to an appropriate depth. Such a technique results in a complex and expensive process. It is therefore proposed to deposit (step,) the undoped silicon oxide layer,in-situ immediately after the arsenic doped silicon oxide layer,has been deposited (step,) and before etching takes place (step,). It is thus possible to remove the CVD of the undoped silicon oxide, thereby simplifying the overall process and yielding a device having improved performance characteristics.

Method of forming a buried plate

A process for DRAM cell production includes (1) depositing a layer of a first substance in a trench; (2) depositing a first layer of a second substance in said trench; (3) growing an interfacial layer of oxide between said layer of said first substance and said first layer of said second substance, and between side walls of said trench and said first layer of said second substance; (4) applying an anisotropic etching substance to the surface of said first layer of said second substance, thereby exposing said interfacial layer of oxide; (5) applying a second etching substance to the surface of said first layer of said second substance thereby substantially removing said interfacial layer of oxide; and (6) depositing a second layer of said second substance in said trench. The process reduces the contact resistance of the buried strap and improves the production yield for low temperature performance cells.

Growing community of inventors

Villach, Austria

Guenther Koffler