Lsi Logic Corporation

David Chan

Sheldon Aronowitz

David C Lee

Valeriy K Sukharev

Wai Lo

James O Kimball

John Haywood

Arvind Kamath

Venkatesh P Gopinath

Rajiv L Patel

Ken Rafftesaeth

Embodiments of the invention include a calibration standard for semiconductor metrology tools. The standard comprises a substrate having a surface with a calibration layer formed thereon. A protective layer is formed over the underlying calibration layer. The calibration layer and protective layer are each formed to precise tolerances. The invention also includes methods for forming a calibration standard for semiconductor metrology tools.

Thin film CMOS calibration standard having protective cover layer

A shallow isolating trench is formed in a semiconductor wafer between active component areas to electrically isolate the active components from each other. The isolating trench is primarily formed of an insulating material, such as an oxide, in a recess formed into the wafer. An etch resistant material, such as BTBAS nitride, is placed over the insulating material in the recess. The etch resistant material protects the insulating material from erosion due to subsequent semiconductor fabrication process steps, so the integrity of the isolating trench and the planarity of the wafer are generally maintained.

Etch resistant shallow trench isolation in a semiconductor wafer

Provided are methods for fabricating hardened composite thin layer gate dielectrics. According to preferred embodiments of the present invention, composite gate dielectrics may be produced as bilayers having oyxnitride portions with nitrogen contents above 10 atomic percent, while avoiding the drawbacks of prior art nitridization methods. In one aspect of the present invention, a hardened composite thin layer gate dielectric may be formed by deposition of a very thin silicon layer on a very thin oxide layer on a silicon substrate, followed by low energy plasma nitridization and subsequent oxidation of the thin silicon layer. In another aspect of the invention, low energy plasma nitridization of a thin oxide layer formed on a silicon substrate may be followed by deposition of a very thin silicon layer and subsequent oxidation, or additional low energy plasma nitridization and then oxidation, of the thin silicon layer.

Composite semiconductor gate dielectrics

Provided is a method of fabricating gate dielectric layers having variable thicknesses and compositions over different regions of a semiconductor wafer. In a preferred embodiment of the present invention, a gate oxide layer is first grown over the various regions. Regions that are to have a relatively thicker, unhardened gate dielectric are masked and the wafer is exposed to a remote low energy nitrogen plasma. After the nitridization process is completed, the mask is removed and the wafer is exposed to further oxidation. The regions where oxynitrides have been formed act as a barrier to the oxidation process. Consequently, different oxide thicknesses can be grown on the same wafer, thinner and hardened where nitridization has been performed, and thicker and not hardened in those regions that were masked during the nitridization. Variable thickness gate dielectrics in accordance with the present invention may be particularly advantageous in semiconductor integrated circuits involving both digital and analog devices.

Method of forming variable thickness gate dielectrics

Growing community of inventors

San Jose, CA, United States of America

David Chan