• Meakin, Naomi R.
• Gammon, Peter M.
• Walker, Marc
• Ashley, Tim
• Jefferies, Richard
• Roberts, Joseph
• Vavasour, Oliver J.
• Chalker, Paul R.

Abstract

<jats:title>Abstract</jats:title><jats:p>In this work, the role of HCl treatments on InSb surfaces and InSb–Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> dielectric interfaces is characterised. X-ray photoelectron spectroscopy measurements indicate that HCl diluted in and rinsed with isopropanol (IPA) results in a surface layer of InCl<jats:sub>3</jats:sub> which is not present for similar HCl-water processes. Furthermore, this InCl<jats:sub>3</jats:sub> layer desorbs from the surface between 200 °C and 250 °C. Metal–oxide–semiconductor capacitors were fabricated using atomic layer deposition of Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> at 200 °C and 250 °C and the presence of InCl<jats:sub>3</jats:sub> was associated with a +0.79 V flatband voltage shift. The desorption of the InCl<jats:sub>3</jats:sub> layer at 250 °C reversed this shift but the increased process temperature resulted in increased interface-trapped charge (<jats:italic>D</jats:italic><jats:sub>it</jats:sub>) and hysteresis voltage (<jats:italic>V</jats:italic><jats:italic><jats:sub>H</jats:sub></jats:italic>). This shift in flatband voltage, which does not affect other figures of merit, offers a promising route to manipulate the threshold voltage of MOS transistors, allowing enhancement-mode and depletion-mode devices to be fabricated in parallel.</jats:p>

Topics

• impedance spectroscopy
• surface
• x-ray photoelectron spectroscopy
• semiconductor
• atomic layer deposition