A Silicon Nitride Based Shallow Trench Isolation with Side-Gate for CMOS Integration with MEMS Components for System-On-Chip Applications

ABSTRACTWe have developed a hydrofluoric acid (HF) resistant, composite shallow trench isolation (STI) process for MOSFETs utilizing silicon nitride as isolation material for on-chip integration of micro-electro-mechanical (MEMS) resonators and CMOS devices. Peripheral leakage currents in silicon nitride isolated MOSFETs are suppressed by employing an independently controlled polysilicon side-gate, surrounding the active area of the devices. Electrostatic control of the threshold voltage at the device periphery alleviates the need for edge implants, resulting in increased thermal budget. Compatibility with HF release processes and high temperature anneal cycles allows integration of MEMS components in close proximity to CMOS devices for system-on-chip applications. nMOSFET devices fabricated using this composite STI process show excellent device characteristics.

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Micro-Raman Spectroscopy Evaluation of the Local Mechanical Stress in Shallow Trench Isolation CMOS Structures: Correlation with Defect Generation and Diode Leakage

10.31399/asm.cp.istfa1998p0011 ◽

1998 ◽

Author(s):

I. De Wolf ◽

G. Groeseneken ◽

H.E. Maes ◽

M. Bolt ◽

K. Barla ◽

...

Keyword(s):

Raman Spectroscopy ◽

Mechanical Stress ◽

Defect Formation ◽

Active Area ◽

Wet Oxidation ◽

Leakage Currents ◽

Shallow Trench Isolation ◽

Micro Raman Spectroscopy ◽

Silicon Devices ◽

Trench Isolation

Abstract It is shown, using micro-Raman spectroscopy, that Shallow Trench Isolation introduces high stresses in the active area of silicon devices when wet oxidation steps are used. These stresses result in defect formation in the active area, leading to high diode leakage currents. The stress levels are highest near the outer edges of line structures and at square structures. They also increase with decreasing active area dimensions.

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Selective Chemical Mechanical Polishing of Silicon Dioxide over Silicon Nitride for Shallow Trench Isolation Using Ceria Slurries

Journal of The Electrochemical Society ◽

10.1149/1.3230624 ◽

2009 ◽

Vol 156 (12) ◽

pp. H936 ◽

Cited By ~ 21

Author(s):

P. R. Dandu Veera ◽

Shivaji Peddeti ◽

S. V. Babu

Keyword(s):

Silicon Nitride ◽

Silicon Dioxide ◽

Chemical Mechanical Polishing ◽

Mechanical Polishing ◽

Shallow Trench Isolation ◽

Trench Isolation ◽

Selective Chemical

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Colloidal Silica based High Selectivity Shallow Trench Isolation (STI) Chemical Mechanical Polishing (CMP) Slurry

MRS Proceedings ◽

10.1557/proc-867-w8.5 ◽

2005 ◽

Vol 867 ◽

Cited By ~ 2

Author(s):

Kyoung-Ho Bu ◽

Brij M. Moudgil

Keyword(s):

Silicon Nitride ◽

Chemical Mechanical Polishing ◽

Colloidal Silica ◽

Sodium Dodecyl ◽

Mechanical Polishing ◽

Wafer Surface ◽

Shallow Trench Isolation ◽

Pattern Size ◽

Trench Isolation ◽

Silica Slurry

AbstractAmong various properties of chemical mechanical polishing (CMP) slurry, selectivity plays a key role in global planarization of high density and small pattern size shallow trench isolation (STI) process. Lack of adequate selectivity can lead to defects such as dishing and erosion. To improve the selectivity of STI CMP process, CMP characteristics of silica and silicon nitride wafer were investigated using colloidal silica slurry as a function of slurry pH. Sodium dodecyl sulfate (SDS), an anionic surfactant, was added to increase the selectivity of the slurry. As a result, selectivity increased from 3 to 25. It was concluded that selective passivation layer formed on silicon nitride wafer surface at acidic slurry pH range was responsible for the observed selectivity increase. Adsorption characteristics of SDS on silica and silicon nitride were measured as a function of slurry pH and concentration of SDS. As indicated by zeta potential behavior under acidic pH conditions, SDS adsorption on silicon nitride was significantly higher han silica due to the electrostatic forces. Significantly higher SDS coating on silicone nitride seems to have resulted in lubrication layer leading to increased polishing selectivity.

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N-Channel Sub-Threshold Leakage “Pipes” Generated From Micro-Twinning Near Shallow Trench Isolation Interface

ISTFA 2002: Conference Proceedings from the 28th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2002p0599 ◽

2002 ◽

Author(s):

Erick M. Spory

Keyword(s):

Compressive Stress ◽

Process Parameters ◽

Shallow Trench Isolation ◽

Silicon Lattice ◽

Corner Region ◽

Twin Defect ◽

Close Proximity ◽

Trench Isolation ◽

Pipe Formation ◽

Very High

Abstract The pursuit of shorter and narrower channel transistor processes, especially those employing Shallow Trench Isolation (STI), can readily produce devices that are increasingly susceptible to the formation of sub-threshold, leakage-generating defects. Specifically, STI N-channel devices exhibiting lengths at or below 0.35 um and with widths below 1 um, are at a heightened risk of developing a channel micro-twin defect “pipe” due to the very high compressive stress within the silicon lattice. Wider, sub-0.35 um devices can also exhibit the problem if their channels are in extremely close proximity to an active/STI corner region. Modification of the relevant process parameters can significantly alleviate this stress and reduce the frequency of “pipe” formation.

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Stress-induced leakage currents of CMOS ULSI devices with shallow trench isolation

10.1117/12.360556 ◽

1999 ◽

Cited By ~ 1

Author(s):

Ravi Sundaresan ◽

Chock H. Gan ◽

Igor V. Peidous

Keyword(s):

Leakage Currents ◽

Shallow Trench Isolation ◽

Trench Isolation

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Composite Shallow Trench Isolation Using Silicon Nitride and Doped Polysilicon for Ultra-Low Power CMOS

ECS Meeting Abstracts ◽

10.1149/ma2007-02/25/1299 ◽

2007 ◽

Keyword(s):

Silicon Nitride ◽

Low Power ◽

Ultra Low Power ◽

Shallow Trench Isolation ◽

Trench Isolation ◽

Low Power Cmos

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Silicon Corrosion during Selective Silicon Nitride Etch with Hot Diluted Hydrofluoric Acid

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.314.107 ◽

2021 ◽

Vol 314 ◽

pp. 107-112

Author(s):

Philippe Garnier ◽

Thomas Massin ◽

Corentin Chatelet ◽

Emmanuel Oghdayan ◽

Jeffrey Lauerhaas ◽

...

Keyword(s):

Silicon Nitride ◽

Hydrofluoric Acid ◽

Orthophosphoric Acid ◽

Deionized Water ◽

Silicon Surfaces ◽

Shallow Trench Isolation ◽

Trench Isolation

Silicon nitride is commonly etched by hot orthophosphoric acid. Hot diluted hydrofluoric acid is hereby used as an alternative. Nonetheless, in presence of silicon surfaces, some corrosion has been evidenced, degrading significantly active areas during the STI (Shallow Trench isolation) integration. Oxygen in hot deionized water or hot HF generates this corrosion and selecting a relevant chemical oxide before dispensing hot diluted HF is key in solving the concern.

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