AVS 51st International Symposium
    Surface Science Thursday Sessions
       Session SS3-ThM

Paper SS3-ThM3
Real-time and In-situ Surface Stress and STM Measurements and their Application to Halogen Etching of Silicon Surfaces

Thursday, November 18, 2004, 9:00 am, Room 213B

Session: Halogen and Oxygen Surface Reactions and Etching
Presenter: T. Narushima, Trinity College Dublin, Ireland
Authors: T. Narushima, Trinity College Dublin, Ireland
N. Kinahan, Trinity College Dublin, Ireland
J.J. Boland, Trinity College Dublin, Ireland
Correspondent: Click to Email
All reactions between surfaces and other species induce strain at the interface to compensate for size differences, electronegativity differences, morphology changes etc. These days, to understand detailed reaction mechanism, contribution of the strain is an important factor which cannot be ignored. The resolution of SPM, however, is poor for this purpose because it does not have absolute but relative resolution. This makes strain determination via this visual method unreliable. In this presentation, we will demonstrate how this induced strain can be determined more accurately through simultaneous surface stress measurements and STM observations as a function of time. To realise this, we have designed a special monitoring system. Surface stress can be readily measured via a capacitance method. The bending of a simple cantilever was measured as a change of capacitance between sample itself and reference electrode. Change from an initial capacitance value corresponds to sample bending which indicates the surface stress change. For surface structure observation, we used conventional STM. In this configuration, conventional direct current heating of the cantilever Si sample is not possible. To heat and prepare samples we used an infrared heating source. This method allowed us to heat sample via a non-contact and static means, which is preferable for STM observation as it induces no noise effects during imaging. At high temperature, surface stress measurements become quite difficult, because high temperature induces thermal stress at interface between heterogeneous materials of sample holder. To avoid this affect, we chose a good combination of quartz and super invar that both have low thermal expansion coefficients and almost equivalent values. We will describe the application of this system to the study of halogen etching of Si surfaces.