High-resolution transmission electron microscopy of silicon re-growth at controlled elevated temperatures

Abstract

Direct observations of atomic surf ace rearrangements and dislocation reactions using high-resolution transmission electron microscope (TEM) techniques have been described for gold and for cadmium telluride^1–6. A major disadvantage of these experiments has been that they rely on the heating effect of the imaging electron beam to raise the temperature of the sample so that thermally activated processes can be induced. This severely restricts the materials which can be studied and significantly reduces the control of the observer in bringing about changes of interest. We have previously suggested⁴ that many solids would be open to such investigation if an appropriate temperature range could be reached. Using a simple Arrhenius kinetic law, we estimated, for example, that silicon would need to be held at ∼600 °C to make equivalent observations to those seen in CdTe. Recognizing the contemporary technological applications of silicon, such a step would be important in fundamental studies of device circuits. We report here that this type of imaging can indeed be performed successfully, without recourse to specialized instrumentation, and that new insights can be gained concerning defect production phase transformations in this important material.