HIGH QUALITY SYNTHETIC QUARTZ CRYSTAL GROWTH FOR THE INFORMATION TECHNOLOGY
ARMANDO H. SHINOHARA
Federal University of Pernambuco, Center of Technology and Geoscience, Department of Mechanical Engineering, Division of Materials Engineering, 50740-310 Cidade Universitária, Recife, PE, Brazil.
Presented by ALCIDES N. SIAL
Since the first application of piezoelectric property of quartz crystal in the electrical circuit for frequency control in 1921 (Heising, 1985), its application has been increased in several areas such as in the telecommunication system networks and electronic microprocessors mainly due to its high stability and effective cost/performance. However, due to the limited volume of natural quartz of quality and its high cost for such applications, a technology known as hydrothermal process was established in 70's for the mass production of synthetic quartz crystals. This technology involve quartz seeds and lascas of natural quartz as nutrient to grow the synthetic quartz crystals. Nowadays, the annual production of the synthetic quartz in the world is about 2.000 ton.
The advent of cellular and satellite networks of high frequency, smaller, cost effective resonators demand improved uniformity in quartz materials (Balascio and Lind, 1997). Even though, the final quality depends mainly on the growth conditions, it is well known the seed quality play an important role. Therefore, the seed technology is crucial. One of methods is use of high quality natural quartz seeds to grow synthetic quartz crystals of high crystallline perfection. At present, there are some supplies of suitable crystals from Madagascar, but Brazil remains at present the most important source. Even though there are possibilities that large areas are still geologically unexplored, large well formed crystals are becoming rare, very expensive and involving a very specialized techniques for the inspection of big blocks.
Since the establishment of synthetic quartz technology, several efforts have been done to improve the crystalline perfection and purity of synthetic quartz crystals. In this presentation, results of recent research works to obtain high quality synthetic quartz crystals in Brazil and in abroad are summarized (Shinohara et al., 2000). Furthermore, the present Brazilian conditions in terms of production of natural quartz crystals for synthetic quartz industries are presented and discussed. (May 19, 2000)
*E-mail: shinohara@demec.ufpe.br
Publication Dates
-
Publication in this collection
05 Jan 2001 -
Date of issue
Dec 2000
