Tip-induced band bending on Sr/Si(100)-2×3 reconstructed surface

Wenhan Du,Jingjing Yang,Bing Wang,Xifang Zhu,Lei Chen,Yu Zhao,Jinxiang Ma,Chao Xiong,Keke Zhang

doi:10.1063/1.4998918

Abstract

Using Vary-temperature Scanning Tunnelling Microscopy (VT-STM), the geometric and electronic structures of technological important Sr/Si(100)-2×3 surface were investigated. Two important findings explained in this research. First, a phenomenon similar to quantum corral observed in the empty state STM image that near the bottom of the conduction band. This is aroused from the surface vacancies and phase boundary in the Sr/Si(100)-2×3 surface. And a new Sr/Si(100)-2×6 reconstructed structure coexist with Sr/Si(100)-2×3 surface has been prepared by accurately controlling the annealing temperature, both surface’s geometric structures can be described by dimer vacancy model. Second, tip-induced band bending phenomenon was observed in the Sr/Si(100)-2×3 surface at substrate temperature range from 76K to 300K. Experimental LDOS results from n and p-type silicon substrate confirms 0.3eV up the motion of the valence band minimum compare with bare Si(100)-2×1 surface. Buckled and unbuckled silicon dimer coexisting in the Sr/Si(100)-2×3 reconstructed surface contribute to the tip-induced band bending and energy band gap widen phenomenon. Which confirms that Sr atoms transfer electrons to the nearby silicon dimers, make the first layer silicon dimers kept at unbuckled state.

Highlights

The shrinkage of the dimension of COMS device has led to higher gate leakage current
Si(100)- 2×1 is that the former behave widen energy band gap phenomenon, while the latter behave narrower energy band gap phenomenon. This proves that silicon dimers dominate the electronic structure of Sr/Si(100)-2×3 surface, and Sr atom donates an electron to the nearby silicon dimer, forming buckled and unbuckled dimers
Using STM and STS, we investigated the geometric and electronic structures of Sr/Si(100)-2×3 reconstructed surface

Summary

INTRODUCTION

The shrinkage of the dimension of COMS device has led to higher gate leakage current. In order to reduce this, crystalline high k oxides, such as SrTiO3, should replace the traditional gate oxide of SiO2 and HfO2.1–4 Owing to its high activity of surface silicon atom dangling bond, amorphous silicon oxide formed during the high-temperature growth process. This forbids the hetero-epitaxial growth of the SrTiO3 thin film on silicon substrate. Tip-induced band bending phenomenon was found on this surface, which helped to deepen the understanding of this first well ordered stable reconstructed structure of Sr/Si(100) surface system

EXPERIMENT

RESULTS AND DISCUSSIONS

CONCLUSIONS