Dual Work Function CMOS Gate Technology Based on Metal Interdiffusion

ABSTRACTIn this paper we propose a new metal-gate CMOS technology that uses a combination of two metals to achieve a low threshold voltage for both n- and p-MOSFET's. One of the gate electrodes is formed by metal interdiffusion so that no metal has to be etched away from the gate dielectric surface. Consequently, this process does not compromise the integrity and electrical reliability of the gate dielectric. This new technology is demonstrated for the Ti-Ni metal combination that produces gate electrodes with 3.9 eV and 5.3 eV work functions for n-MOS and p-MOS devices respectively.

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Impact of Galvanic Corrosion on Metal Gate Stacks

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.145-146.215 ◽

2009 ◽

Vol 145-146 ◽

pp. 215-218

Author(s):

Masayuki Wada ◽

Sylvain Garaud ◽

I. Ferain ◽

Nadine Collaert ◽

Kenichi Sano ◽

...

Keyword(s):

Gate Dielectric ◽

Gate Dielectrics ◽

Galvanic Corrosion ◽

Gate Stacks ◽

Metal Gate Electrodes ◽

Metal Gate ◽

Fermi Level Pinning ◽

Gate Electrodes ◽

High K ◽

Work Functions

High-k gate dielectrics (HK), such as HfO2 or HfSiON, are being considered as the gate dielectric option for the 45nm node and beyond. In order to alleviate the Fermi-level pinning issue and to enhance the CET (Capacitive Effective Thickness) by generating the depletion layer in poly-Silicon gate, metal gate electrodes with proper work functions (WF) have to be used on the high-k dielectrics.

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Electrical reliability aspects of HfO2 high-k gate dielectrics with TaN metal gate electrodes under constant voltage stress

Microelectronics Reliability ◽

10.1016/j.microrel.2005.02.004 ◽

2006 ◽

Vol 46 (1) ◽

pp. 69-76 ◽

Cited By ~ 43

Author(s):

S. Chatterjee ◽

Y. Kuo ◽

J. Lu ◽

J.-Y. Tewg ◽

P. Majhi

Keyword(s):

Gate Dielectrics ◽

Constant Voltage ◽

Metal Gate Electrodes ◽

Metal Gate ◽

Gate Electrodes ◽

High K ◽

Voltage Stress ◽

Electrical Reliability

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Thermal stability of Hf/sub x/Ta/sub y/N metal gate electrodes for advanced MOS devices

IEEE Electron Device Letters ◽

10.1109/led.2005.863563 ◽

2006 ◽

Vol 27 (3) ◽

pp. 148-150 ◽

Cited By ~ 12

Author(s):

Chin-Lung Cheng ◽

Kuei-Shu Chang-Liao ◽

Tzu-Chen Wang ◽

Tien-Ko Wang ◽

Howard Chih-Hao Wang

Keyword(s):

Thermal Stability ◽

Metal Gate Electrodes ◽

Metal Gate ◽

Gate Electrodes ◽

Mos Devices ◽

Thermal Stability Of

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HfxTayNz Metal Gate Electrodes for Advanced MOS Devices Applications

2006 International Symposium on VLSI Technology, Systems, and Applications ◽

10.1109/vtsa.2006.251091 ◽

2006 ◽

Cited By ~ 1

Author(s):

Chin-lung Cheng ◽

Kuei-shu Chang-Liao ◽

Tzu-chen Wang ◽

Tien-ko Wang ◽

Howard Wang

Keyword(s):

Metal Gate Electrodes ◽

Metal Gate ◽

Gate Electrodes ◽

Mos Devices

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Application of group electronegativity concepts to the effective work functions of metal gate electrodes on high-κ gate oxides

Microelectronic Engineering ◽

10.1016/j.mee.2007.04.130 ◽

2007 ◽

Vol 84 (9-10) ◽

pp. 2196-2200 ◽

Cited By ~ 33

Author(s):

J.K. Schaeffer ◽

D.C. Gilmer ◽

C. Capasso ◽

S. Kalpat ◽

B. Taylor ◽

...

Keyword(s):

Metal Gate Electrodes ◽

Metal Gate ◽

Gate Oxides ◽

Effective Work ◽

Gate Electrodes ◽

Group Electronegativity ◽

Work Functions

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Compatibility of HfxTayN metal gate electrode with HfOxNy gate dielectric for advanced CMOS technology

Microelectronic Engineering ◽

10.1016/j.mee.2006.06.005 ◽

2006 ◽

Vol 83 (11-12) ◽

pp. 2516-2521

Author(s):

Kuei-Shu Chang-Liao ◽

Hsin-Chun Chang ◽

B.S. Sahu ◽

Tzu-Chen Wang ◽

Tien-Ko Wang

Keyword(s):

Gate Dielectric ◽

Cmos Technology ◽

Gate Electrode ◽

Metal Gate

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Molybdenum as a Gate Electrode for Deep Sub-Micron CMOS Technology

MRS Proceedings ◽

10.1557/proc-611-c3.2.1 ◽

2000 ◽

Vol 611 ◽

Cited By ~ 20

Author(s):

Pushkar Ranade ◽

Yee-Chia Yeo ◽

Qiang Lu ◽

Hideki Takeuchi ◽

Tsu-Jae King ◽

...

Keyword(s):

Work Function ◽

Elevated Temperatures ◽

Coefficient Of Thermal Expansion ◽

Cmos Technology ◽

Gate Electrode ◽

Short Channel ◽

Gate Electrodes ◽

Channel Effects ◽

Work Functions ◽

Gate Resistance

ABSTRACTMolybdenum has several properties that make it attractive as a CMOS gate electrode material. The high melting point (∼2610°C) and low coefficient of thermal expansion (5×10−6/°C, at 20 °C) are well suited to withstand the thermal processing budgets normally encountered in a CMOS fabrication process. Mo is among the most conductive refractory metals and provides a significant reduction in gate resistance as compared with doped polysilicon. Mo is also stable in contact with SiO2 at elevated temperatures. In order to minimize short-channel effects in bulk CMOS devices, the gate electrodes must have work functions that correspond to Ec (NMOS) and Ev (PMOS) in Si. This would normally require the use of two metals with work functions differing by about 1V on the same wafer and introduce complexities associated with selective deposition and/or etching. In this paper, the dependence of the work function of Mo on deposition and annealing conditions is investigated. Preliminary results indicate that the work function of Mo can be varied over the range of 4.0-5.0V by a combination of suitable post-deposition implantation and annealing schemes. Mo is thus a promising candidate to replace polysilicon gates in deep sub-micron CMOS technology. Processing sequences which might allow the work function of Mo to be stabilized on either end of the Si energy band gap are explored.

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