Impact of plasma post-nitridation on HfO2/Al2O3/SiGe gate stacks toward EOT scaling

Han, Jae‐Hoon; Zhang, Rui; Osada, Takenori; Hata, Masahiko; Takenaka, Mitsuru; Takagi, Shinichi

doi:10.1016/j.mee.2013.03.013

Cited by 24 publications

(17 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, there have been studies on controlling the growth of both Si and Ge oxides at the SiGe/high-k (Al 2 O 3 ) interface by manipulating the composition of the metal contact layer, plasma postnitridation, preatomic layer deposition (ALD) dosing, and wet chemical sulfur passivation. [12][13][14][15][16][17] with the ratio of 1:1:500 for 2 min followed by rinsing with UPW for 1 min and blown dry with N 2 . Oxides were removed by immersion in HF:HCl:H 2 O with the ratio of 1:3:300 for 5 min.…”

Section: Introductionmentioning

confidence: 99%

Reaction of aqueous ammonium sulfide on SiGe 25%

Heslop

Peckler

Muscat

2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

View full text Add to dashboard Cite

SiGe 25% substrates were treated with aqueous solutions of ammonium sulfide with and without added acid to understand the adsorption of sulfur on the surface. X-ray photoelectron spectroscopy showed no sulfide layer was deposited from aqueous (NH 4 ) 2 S alone and instead both Si and Ge oxides formed during immersion in the sulfur solution. The addition of hydrofluoric and hydrochloric acids dropped the pH from 10 to 8 and deposited sulfides, yet increased the oxide coverage on the surface and preferentially formed Ge oxides. The sulfur coverage grew with increasing concentrations of acid in the aqueous (NH 4 ) 2 S. The simultaneous deposition of O and S is suspected to be the result of oxidized sulfur species in solution. Metal-insulator-semiconductor capacitor (MISCAP) devices were fabricated to test the electrical consequences of aqueous ammonium sulfide wet chemistries on SiGe. MISCAPs treated with acidic ammonium sulfide solutions contained fewer interface defects in the valence band region. The defect density (D it ) was on the order of 10 þ12 cm -2 eV À1. The flat band voltage shift was lower after the acidic ammonium sulfide treatment, despite the presence of surface oxides. Adsorption of S and potentially O improved the stability of the surface and made it less electrically active.

show abstract

Section: Introductionmentioning

confidence: 99%

Reaction of aqueous ammonium sulfide on SiGe 25%

Heslop

Peckler

Muscat

2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

View full text Add to dashboard Cite

show abstract

“…For the pMOSFETs of all the four wafers, the frequency exponent γ is approximately equal to 1, indicating an uniformly distributed border trap density probed from low frequency noise measurement from 3 Hz to 10 kHz. The r trap depth Z corresponding with a frequency f is given by: [1] in which a t is the tunneling coefficient.…”

Section: Resultsmentioning

confidence: 99%

“…The high mobility makes Ge a promising channel material for both low power and high performance applications of advanced devices (1). On the other hand, gate stack engineering is challenging in Ge devices, in view of the higher density of interface states typically observed (2).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Impact of Gate Stack Dielectric on Intrinsic Voltage Gain and Low Frequency Noise in Ge pMOSFETs

et al. 2015

View full text Add to dashboard Cite

This paper presents an experimental analysis of the gate stack dielectric influence on low frequency noise and intrinsic voltage gain (A V ) in planar germanium pMOSFETs with a HfO 2 /Al 2 O 3 gate stack. The Av is studied not only at room temperature, but also from 25 to 150 °C. It is observed that neither the HfO 2 -thickness nor the plasma oxidation power have a significant impact on the noise power spectral density and intrinsic voltage gain (A V ). In contrast, the thinner Al 2 O 3 -layer is more susceptible to any damage during the fabrication processes, which increases the interface state density (N IT ) between the Ge surface and gate stack layer, resulting in a device performance degradation. Furthermore, from high temperature point of view, the A V is predominantly dominated by the carrier mobility degradation, which reduces the transconductance.

show abstract

“…11 Despite low D it , even for HfO 2 /Al 2 O 3 bilayers, post-nitridation limits the equivalent oxide thickness (EOT) scaling to 3.0 nm. 12 This may be related to the challenge for fully nitriding Ge atoms in the presence of the more reactive Si atoms.…”

mentioning

confidence: 99%

Nitride passivation of the interface between high-k dielectrics and SiGe

Sardashti

Tang

et al. 2016

Applied Physics Letters

View full text Add to dashboard Cite

In-situ direct ammonia (NH3) plasma nitridation has been used to passivate the Al2O3/SiGe interfaces with Si nitride and oxynitride. X-ray photoelectron spectroscopy of the buried Al2O3/SiGe interface shows that NH3 plasma pre-treatment should be performed at high temperatures (300 °C) to fully prevent Ge nitride and oxynitride formation at the interface and Ge out-diffusion into the oxide. C-V and I-V spectroscopy results show a lower density of interface traps and smaller gate leakage for samples with plasma nitridation at 300 °C.

show abstract

Impact of plasma post-nitridation on HfO2/Al2O3/SiGe gate stacks toward EOT scaling

Cited by 24 publications

References 9 publications

Reaction of aqueous ammonium sulfide on SiGe 25%

Reaction of aqueous ammonium sulfide on SiGe 25%

Impact of Gate Stack Dielectric on Intrinsic Voltage Gain and Low Frequency Noise in Ge pMOSFETs

Nitride passivation of the interface between high-k dielectrics and SiGe

Contact Info

Product

Resources

About