The Schottky barrier Heights between Fe3Si and GaAs with in-situ XPS and I-V Measurements
Date Issued
2014
Date
2014
Author(s)
Syu, Bei-Zhen
Abstract
Metal-semiconductor (MS) interfaces are an essential part in electronic and spintronic devices; therefore, Schottky barrier heights (SBH) are clearly the most important property of an MS interface. For over 70 years, various models have been proposed to explain how these rectifying barriers are determined. But thus far no theory emerges which gives explicit account of the experimental results. According to the prediction of International Technology Roadmap for Semiconductors (ITRS), the physical gate length of device will be scaling down to 10 nm in 2021. In ultimate CMOS technology with III-V semiconductors as the channel material, extremely low Ohmic contacts are demanded, in which the understanding and manipulation of the SBH is a must to achieve the low resistivity.
However, the formation of the Schottky barrier height (SBH) is an extremely complex problem because of the dependence of the SBH on the atomic structure of the metal-semiconductor (MS) interface. In order to study the mysterious SBH, we designed the series experiments. In this work, the growth of Fe¬3Si on GaAs was carried out in a multi-chamber growth/analysis system, including a GaAs-based III–V molecular beam epitaxy (MBE) chamber, a As-free metal MBE chamber and an X-ray vacuum (UHV) modules.
The temperature dependence of the current-voltage characteristics of Fe3Si/GaAs(100) was measured by contact probe techniques. Our results indicate that the logarithmic plot of current as a function of bias voltage across the Schottky diode gives a linear relationship.
Comparison of results of I-V measurement, we precisely obtained the Schottky barrier heights from XPS and UPS measurements. Furthermore, the ionization energy of GaAs(100) 4x6 clean surface and work function of Fe3Si were measured by UV source HeI lamp in the same XPS chamber. Also, due to the larger escape length of XPS photoelectrons, it is possible to measure the band bending in the substrate at relatively high overlayer depths independently from the overlayer band bending. The band diagrams of Fe3Si/GaAs were absolutely shown clear in this experiments. Furthermore, vacuum energy misalignment at Fe3Si and GaAs interface was demonstrated and the SBH have been directly determined via this method without any assumptions.
Subjects
蕭特基能障
砷化鎵
鐵矽化合物
光電子激發能譜
Type
thesis
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