Chapter 1 Introduction to Oxygen in Silicon

Abstract

The chapter presents an introduction to oxygen in silicon. Although several techniques have been utilized to convert polysilicon into single crystals of silicon, two techniques have dominated the production of silicon single crystals, because they meet the requirements of the microelectronic device technology. One is a zone-melting method commonly called the float-zone (FZ) method and the other is a pulling method generally called the Czochralski (CZ) method, although it should be called more properly the Teal-Little method. With regard to the characterization of lattice defects generated by oxygen precipitation in CZ silicon, there have been a large variety of observations by means of transmission electron microscopy (TEM) for the materials heat treated under various conditions. In summary, no matter how much oxygen is incorporated in silicon wafers used for the fabrication of electronic devices, the impurity critically affects the properties and yield of the devices because of three factors: (1) internal defects produced by oxygen precipitation benefit the gettering effect (IG); (2) mechanical strength of silicon wafers greatly depends on the oxygen concentration and state—that is, dissolved oxygen atoms or SiO, precipitates; and (3) oxygen donors are formed at a specific temperature. Consequently, it is very important to understand the behavior of oxygen from the electrical, chemical, and structural points of view, and to control not only the concentration, but also the precipitation in silicon.