Abstract
MOS devices based on III-V semiconductors and thin high-k dielectric layers offer possibilities for improved transport properties. Here, we have studied the interface structure and chemical composition of realistic MOS gate stacks, consisting of a W or Pd metal film and a 6- or 12-nm-thick HfO2 layer deposited on InAs, with Hard X-ray Photoemission Spectroscopy. In and As signals from InAs buried more than 18 nm below the surface are clearly detected. The HfO2 layers are found to be homogeneous, and no influence of the top metal on the sharp InAs-HfO2 interface is observed. These results bridge the gap between conventional photoemission spectroscopy studies on various metal-free model samples with very thin dielectric layers and realistic MOS gate stacks.
Highlights
We have studied the interface structure and chemical composition of realistic MOS gate stacks, consisting of a W or Pd metal film and a 6- or 12-nm-thick HfO2 layer deposited on Indium arsenide (InAs), with Hard X-ray Photoemission Spectroscopy
Very thin homogeneous high-k oxide layers can routinely be formed by atomic layer deposition (ALD),[2,4,5] where even a self-cleaning effect on the native oxide has been observed.[6,7,8,9]
X-ray photoelectron spectroscopy (XPS) has been proven a powerful technique to study the interface between high-k dielectric films and semiconductors like GaAs2,4,7,8 and InAs,[9,10,11,12,13] the latter material being especially promising for electronic applications due to its large electron mobility and high electron injection velocity.[14,15]
Summary
We have studied the interface structure and chemical composition of realistic MOS gate stacks, consisting of a W or Pd metal film and a 6- or 12-nm-thick HfO2 layer deposited on InAs, with Hard X-ray Photoemission Spectroscopy.
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