Browsing by Author "Zhang, QC"

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A TaN-HfO2-Ge pMOSFET with novel SiH4 surface passivation
(2004-09-01)
Wu, N
;
Zhang, QC
;
Zhu, CX
;
Chan, DSH
;
Du, AY
In this letter, we demonstrate a novel surface passivation process for HfO2 Ge pMOSFETs using SiH4 surface annealing prior to HfO2 deposition. By using SiH4 passivation, a uniform amorphous interfacial layer is formed after device fabrication. Electrical results show that the HfO2 Ge MOSFET with Si-passivation exhibits less frequency dispersion, narrower gate leakage current distribution, and a similar to 140% higher peak mobility than that of the device with surface nitridation.
Alternative surface passivation on germanium for metal-oxide-semiconductor applications with high-k gate dielectric
(2004-11-01)
Wu, N
;
Zhang, QC
;
Zhu, CX
;
Chan, DSH
;
Li, MF
An alternative surface passivation process for high-k Ge metal-oxide-semiconductor (MOS) device has been studied. The surface SiH4 annealing was implemented prior to HfO2 deposition. X-ray photoelectron spectroscopy analysis results show that the SiH4 surface passivation can greatly prevent the formation of unstable germanium oxide at the surface and suppress the Ge out-diffusion after the HfO2 deposition. The electrical measurement shows that an equivalent oxide thickness of 13.5 Angstrom and a leakage current of 1.16x10(-5) A/cm(2) at 1 V gate bias was achieved for TaN/HfO2/Ge MOS capacitors with the SiH4 surface treatment. (C) 2004 American Institute of Physics.
Effect of surface NH3 anneal on the physical and electrical properties of HfO2 films on Ge substrate
(2004-05-10)
Wu, N
;
Zhang, QC
;
Zhu, CX
;
Yeo, CC
;
Whang, SJ
Metal-oxide-semiconductor capacitors were fabricated on germanium substrates by using metalorganic-chemical-vapor-deposited HfO2 as the dielectric and TaN as the metal gate electrode. It is demonstrated that a surface annealing step in NH3 ambient before the HfO2 deposition could result in significant improvement in both gate leakage current and the equivalent oxide thickness (EOT). It was possible to achieve a capacitor with an EOT of 10.5 Angstrom and a leakage current of 5.02x10(-5) A/cm(2) at 1 V gate bias. X-ray photoelectron spectroscopy analysis indicates the formation of GeON during surface NH3 anneal. The presence of Ge was also detected within the HfO2 films. This may be due to Ge diffusion at the high temperature (similar to400 degreesC) used in the chemical-vapor deposition process. (C) 2004 American Institute of Physics.