Effect of HCl cleaning on InSb–Al2O3 MOS capacitors. (26th February 2019)

• Record Type: Journal Article
• Authors: Vavasour, Oliver J; Jefferies, Richard; Walker, Marc; Roberts, Joseph W; Meakin, Naomi R; Gammon, Peter M; Chalker, Paul R; Ashley, Tim
• Is Part Of: Semiconductor science and technology. Volume 34:Number 3(2019)
• Publication Date: 2019-02-26
• Subjects: InSb -- III–V -- HCl -- ALD -- Al2O3 -- MOSCAP; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/1361-6641/ab0331
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: In this work, the role of HCl treatments on InSb surfaces and InSb–Al2 O3 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 InCl3 which is not present for similar HCl-water processes. Furthermore, this InCl3 layer desorbs from the surface between 200 °C and 250 °C. Metal–oxide–semiconductor capacitors were fabricated using atomic layer deposition of Al2 O3 at 200 °C and 250 °C and the presence of InCl3 was associated with a +0.79 V flatband voltage shift. The desorption of the InCl3 layer at 250 °C reversed this shift but the increased process temperature resulted in increased interface-trapped charge ( D it ) and hysteresis voltage ( V H ). 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.