AVS 47th International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS+MS-WeM

Paper PS+MS-WeM7
Real-time Observation of Relaxation of Disorder-induced Surface Stress

Wednesday, October 4, 2000, 10:20 am, Room 311

Session: Plasma-Induced Damage
Presenter: T. Narushima, University of Tsukuba, Japan
Authors: T. Narushima, University of Tsukuba, Japan
N. Ueda, University of Tsukuba, Japan
A.N. Itakura, National Research Institute for Metals, Japan
T. Kawabe, University of Tsukuba, Japan
M. Kitajima, National Research Institute for Metals, Japan
Correspondent: Click to Email
We present relaxation of disorder-induced surface stress. The surface stress changes on Si(100) were measured by means of an optical micro-mechanical cantilever technique. The samples were Si(100) cantilevers (450µm x 50µm x 2µm). They were treated by being dipped in 10% HF acid solution for 5 minutes, rinsed with deionized water for 5 minutes, and annealed at 1000K for 30 minutes in a UHV. To introduce disorder to surface, the surfaces were bombarded using an argon plasma with applying negative biases (-30V to -100V) at room temperature. Then, the disordered surfaces were oxidized using an oxygen plasma with applying positive bias (+45V), where the surfaces were subject to electron irradiation. We found a development of compressive stress on the Si surface due to defects produced by ion bombardment. This disorder-induced compressive stress was completely relaxed by the following plasma oxidation. The initial evolution of the surface stress during oxidation on the bombarded surfaces is quite different from that on unbombarded Si(100) surfaces. The disorder-induced stress was also relaxed completely by an exposure to argon plasmas under anodic conditions. The stress relaxation should be promoted not only by oxidation but also by electron irradiation. A possible mechanism of the stress relaxation is surface diffusion of Si adatoms via electron irradiation.