High-k dielectrics on (100) and (110) n-InAs: Physical and electrical characterizations

C H Wang,Y S Chang,C H Diaz,R Droopad,R Oxland,M C Holland,M L Huang,C H Lin,G Vellianitis,G Doornbos,Y Y Chen,C H Hsieh,E Lind,W C Hsu,M Passlack,P Ramvall,G Astromskas,T L Lee,L.-E Wernersson

doi:10.1063/1.4871187

Abstract

Two high-k dielectric materials (Al2O3 and HfO2) were deposited on n-type (100) and (110) InAs surface orientations to investigate physical properties of the oxide/semiconductor interfaces and the interface trap density (Dit). X-ray photoelectron spectroscopy analyses (XPS) for native oxides of (100) and (110) as-grown n-InAs epi wafers show an increase in As-oxide on the (100) surface and an increase in InOx on the (110) surface. In addition, XPS analyses of high-k (Al2O3 and HfO2) on n-InAs epi show that the intrinsic native oxide difference between (100) and (110) epi surfaces were eliminated by applying conventional in-situ pre-treatment (TriMethyAluminium (TMA)) before the high-k deposition. The capacitance-voltage (C-V) characterization of HfO2 and Al2O3 MOSCAPs on both types of n-InAs surfaces shows very similar C-V curves. The interface trap density (Dit) profiles show Dit minima of 6.1 × 1012/6.5 × 1012 and 6.6 × 1012/7.3 × 1012 cm−2 eV−1 for Al2O3 and HfO2, respectively for (100) and (110) InAs surfaces. The similar interface trap density (Dit) on (100) and (110) surface orientation were observed, which is beneficial to future InAs FinFET device with both (100) and (110) surface channel orientations present.

Highlights

III–V compounds, such as GaAs, InGaAs or InAs, have been intensively studied to replace Si as channel material because their high electron mobilities may enable low power and high performance applications for future CMOS
X-ray photoelectron spectroscopy analyses (XPS) analyses of high-k (Al2O3 and HfO2) on n-InAs epi show that the intrinsic native oxide difference between (100) and (110) epi surfaces were eliminated by applying conventional in-situ pre-treatment (TriMethyAluminium (TMA)) before the high-k deposition
AFM scans on both the (100) and (110) n-InAs epi-layers show flat surfaces with root-mean-square roughness less than 2 Å in a 9 μm[2] (3μm × 3μm) area. Both as-grown (100) and (110) n-InAs epitaxial wafers were analyzed by XPS (x-ray photoelectron spectroscopy) to study the surface native oxide composition formed when the layers were removed from the deposition chamber

Summary

Introduction

III–V compounds, such as GaAs, InGaAs or InAs, have been intensively studied to replace Si as channel material because their high electron mobilities may enable low power and high performance applications for future CMOS. InAs is a promising candidate for MOS high-electron-mobility transistor devices[1,2] because it has the highest electron mobility among in the arsenide-based III–V compounds. InAs is a binary compound that could provide a much simpler interface structure and property as compared to InGaAs. there are many studies on high-k/GaAs and high-k/InGaAs structures,[3,4,5,6,7] only a few high-k/InAs structures have been investigated.[8,9] most of studies for high-k/InAs have focused on (100) surface orientation,[10,11] with few (110) InAs investigations published.[12]. Besides the introduction of high electron mobility channels, the device architectures are very important for performance enhancement.

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Conclusion