International Business Machines Corporation

Zeon Corporation

Globalfoundries Inc.

Ravi K Dasaka

Richard Stephan Wise

Masahiro Nakamura

Nicholas C M Fuller

Sebastian Ulrich Engelmann

Geng Wang

Chengwen Pei

Shreesh Narasimha

Paul Christian Parries

Karen A Nummy

Katsunori Onishi

Bidan Zhang

Ahmed Nayaz Noemaun

A silicon nitride cap on a gate stack is removed by etching with a fluorohydrocarbon-containing plasma subsequent to formation of source/drain regions without causing unacceptable damage to the gate stack or source/drain regions. A fluorohydrocarbon-containing polymer protection layer is selectively deposited on the regions that are not to be etched during the removal of the nitride cap. The ability to remove the silicon nitride material using gas chemistry, causing formation of a volatile etch product and protection layer, enables reduction of the ion energy to the etching threshold.

High selectivity nitride removal process based on selective polymer deposition

A stressor structure is formed within a drain region of an access transistor in a dynamic random access memory (DRAM) cell in a semiconductor-on-insulator (SOI) substrate without forming any stressor structure in a source region of the DRAM cell. The stressor structure induces a stress gradient within the body region of the access transistor, which induces a greater leakage current at the body-drain junction than at the body-source junction. The body potential of the access transistor has a stronger coupling to the drain voltage than to the source voltage. An asymmetric etch of a gate dielectric cap, application of a planarization material layer, and a non-selective etch of the planarization material layer and the gate dielectric cap can be employed to form the DRAM cell.

Asymmetric stressor DRAM

Growing community of inventors

Danbury, CT, United States of America

Ravi K Dasaka