International Business Machines Corporation

Other

Infineon Technologies Ag

Porshia Shane Wrschka

Jochen C Beintner

Naim Moumen

Yujun Li

Irene Lennox McStay

Michael Patrick Chudzik

Helmut Horst Tews

Kenneth T Settlemyer, Jr

The structure and method of forming a notched gate MOSFET disclosed herein addresses such problems as device reliability. A gate dielectric (e.g. gate oxide) is formed on the surface of an active area on the semiconductor substrate, preferably defined by an isolation trench region. A layer of polysilicon is then deposited on the gate dielectric. This step is followed by depositing a layer of silicon germanium) (SiGe). The sidewalls of the polysilicon layer are then laterally etched, selective to the SiGe layer to create a notched gate conductor structure, with the SiGe layer being broader than the underlying polysilicon layer. Sidewall spacers are preferably formed on sidewalls of the SiGe layer and the polysilicon layer. A silicide layer is preferably formed as a self-aligned silicide from a polysilicon layer deposited over the SiGe layer, to reduce resistance of the gate conductor. One or more other processing steps (e.g. source and drain implants, extension implants, and pocket lightly doped drain (LDD) implants), gate conductor stack doping, and silicidation are preferably performed in completing the transistor.

Structure and method of forming a notched gate field effect transistor

As disclosed herein, a method is provided, in an integrated circuit, for forming an enhanced capacitance trench capacitor. The method includes forming a trench in a semiconductor substrate and forming an isolation collar on a sidewall of the trench. The collar has at least an exposed layer of oxide and occupies only a 'collar' portion of the sidewall, while a 'capacitor' portion of the sidewall is free of the collar. A seeding layer is then selectively deposited on the capacitor portion of the sidewall. Then, hemispherical silicon grains are deposited on the seeding layer on the capacitor portion of the sidewall. A dielectric material is deposited, and then a conductor material, in that order, over the hemispherical silicon grains on the capacitor portion of the sidewall.

Self-aligned selective hemispherical grain deposition process and structure for enhanced capacitance trench capacitor

A method of forming collar isolation for a trench storage memory cell structure is provided in which amorphous Si (a:Si) and silicon germanium (SiGe) are first formed into a trench structure. An etching process that is selective to a:Si as compared to SiGe is employed in defining the regions in which the collar isolation will be formed. The selective etching process employed in the present invention is a wet etch process that includes etching with HF, rinsing, etching with NHOH, rinsing, and drying with a monohydric alcohol such as isopropanol. The sequence of NHOH etching and rinsing may be repeated any number of times. The conditions used in the selective etching process of the present invention are capable of etching a:Si at a faster rate than SiGe.

Method of forming a collar using selective SiGe/Amorphous Si Etch

A method for fabricating a deep trench etched into a semiconductor substrate is provided by the present invention. The trench is divided into an upper portion and a lower portion and the method allows for the lower portion to be processed differently from the upper portion. After the trench is etched into the semiconductor substrate, a nitride layer is formed over a sidewall of the trench. A layer of oxide is then formed over the nitride layer. A filler material is then deposited and recessed to cover the oxide layer in the lower portion of the trench, followed by the removal of the oxide layer from the upper portion of the trench above the filler material. Once the oxide layer is removed from the upper portion of the trench, the filler material can also be removed, while allowing the oxide layer and the nitride layer to remain in the lower portion of the trench. Silicon is selectively deposited on the exposed nitride layer in the upper portion of the trench. The oxide layer and the nitride layer is then removed from the lower portion. Finally, the lower portion of the trench is processed selectively to nitride, e.g. by one or more capacitor forming processes, and then the upper portion of the trench is processed.

Sacrificial collar method for improved deep trench processing

A method and structure for increasing the area and capacitance of both trench and planar integrated circuit capacitors uses Si nodules deposited on a thin dielectric seeding layer that is absorbed during subsequent thermal processing, thereby avoiding a high resistance layer in the capacitor.

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Danbury, CT, United States of America

Porshia Shane Wrschka