Abstract
The impact of surface treatment on Schottky contacts on a GaN-on-GaN epitaxial layer was comprehensively investigated by combining X-ray photoelectron spectroscopy (XPS) at each step of the treatment process and electrical measurements on Schottky barrier diodes. XPS showed that a photolithography process on a GaN surface reduced the surface oxide and band bending and that the subsequent HCl-based treatment reduced them further. Electrical measurements indicated that HCl treatment after photolithography affected the metal-work-function, ϕM, dependence of the Schottky barrier height, ϕB, resulting in an increase in the slope factor compared with that of the samples without HCl treatment. It is highly likely that the reduction in interface disorder by the chemical treatment led to a reduction in the interface state density at the metal/GaN interface. On the basis of the obtained ϕB–ϕM plots, the charge neutrality level was measured experimentally to be 5.0 eV from the vacuum level and 0.9 eV from the conduction band edge, while the electron affinity was measured to be 4.1 eV.
Highlights
For a sustainable society, electronic device technology that reduces the loss of power electric systems, communication systems, and car electronics is one of the key approaches
The host semiconductor was different, a work has been reported on the effect of surface treatment on the φB−φM relation of SiC Schottky barrier diodes (SBDs).[11]
The effect of the surface treatment on GaN was monitored by X-ray photoelectron spectroscopy (XPS) performed using a monochromatic Al-Kα X-ray source (1486.6 eV) on a separate chip
Summary
Electronic device technology that reduces the loss of power electric systems, communication systems, and car electronics is one of the key approaches. Impact of surface treatment on metalwork-function dependence of barrier height of GaN-on-GaN Schottky barrier diode
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