Chapter 6 - Growth of Crystals

Abstract

This chapter delineates growth of crystals. Many of the devices that are used on a daily basis employ a single crystal element as the heart of the mechanism. A good example is the “quartz crystal” watch. A quartz crystal is made to vibrate under an applied voltage. Its vibrations are coupled to a sensing circuit and translated into seconds, minutes, and hours by using and counting the known resonant frequency of vibration of the crystal. The chapter examines crystal-growing methods and the equipment needed to do so. The method of choice for growing a single crystal depends upon many factors. Most relate to the physical properties of the compound whose single crystal is desired. The most critical element in melt-growth of single crystals is the container, or crucible. The first requirement for selection of a suitable crucible is that the crucible does not react with the melt. The second is that it be thermally shock- resistant. A third is that of operational-temperature capability. A fourth is that it be stable in the chosen atmosphere. These requirements eliminate many potential crucible materials for a given application. The chapter also examines the different type of crystals used both as sensors and as the basis of specific devices used in the electronics industry.