Optical second harmonic intensity images of hydrogen deficiency on H-Si(111) surfaces

Y Miyauchi,H Sano,G Mizutani

doi:10.1380/ejssnt.2006.105

Abstract

In order to obtain the spatial distribution of hydrogen desorption by ultraviolet (UV) laser pulses from a hydrogen terminated Si (H-Si) surface, optical second harmonic (SH) intensity images of the surface have been observed in ultra high vacuum. The observed SH signal included both contributions of the hydrogen deficiency on the H-Si surface and the surface damage. The spatial distribution of the hydrogen deficiency has been obtained from the difference between the SH intensity images before and after the hydrogen re-termination. The hydrogen desorption occurred above the threshold fluence of ∼40 mJ/cm2, and the total amount of the hydrogen desorption increased monotonically as a function of the UV laser pulse energy. It is suggested that the observed hydrogen desorption may have resulted from the laser induced thermal desorption (LITD) mechanism. [DOI: 10.1380/ejssnt.2006.105]

Highlights

The hydrogen terminated silicon (H-Si) single crystal surface is an important model system of adsorbed semiconductor surfaces
In order to obtain the spatial distribution of hydrogen desorption by ultraviolet (UV) laser pulses from a hydrogen terminated Si (H-Si) surface, optical second harmonic (SH) intensity images of the surface have been observed in ultra high vacuum
We demonstrate that spatial distributions of hydrogen deficiency and surface melting on a H-Si(111) surface can be separately obtained from the observed SH intensity images

Summary

20 January 2006

Optical second harmonic intensity images of hydrogen deficiency on H-Si(111) surfaces∗. In order to obtain the spatial distribution of hydrogen desorption by ultraviolet (UV) laser pulses from a hydrogen terminated Si (H-Si) surface, optical second harmonic (SH) intensity images of the surface have been observed in ultra high vacuum. The observed SH signal included both contributions of the hydrogen deficiency on the H-Si surface and the surface damage. The spatial distribution of the hydrogen deficiency has been obtained from the difference between the SH intensity images before and after the hydrogen re-termination. The hydrogen desorption occurred above the threshold fluence of ∼40 mJ/cm, and the total amount of the hydrogen desorption increased monotonically as a function of the UV laser pulse energy. It is suggested that the observed hydrogen desorption may have resulted from the laser induced thermal desorption (LITD) mechanism.

INTRODUCTION

EXPERIMENT

RESULTS AND DISCUSSION

CONCLUSION