It is a real pleasure to write the Foreword for this book, both because I have known and respected its author for many years and because I expect this books publication will mark an important milestone in the continuing worldwide development of microsystems. By bringing together all aspects of microsystem design, it can be expected to facilitate the training of not only a new generation of engineers, but perhaps a whole new type of engineer - one capable of addressing the complex range of problems involved in reducing entire systems to the micro- and nano-domains. This book breaks down disciplinary barriers to set the stage for systems we do not even dream of today. Microsystems have a long history, dating back to the earliest days of mic- electronics. While integrated circuits developed in the early 1960s, a number of laboratories worked to use the same technology base to form integrated sensors. The idea was to reduce cost and perhaps put the sensors and circuits together on the same chip.
By the late-60s, integrated MOS-photodiode arrays had been developed for visible imaging, and silicon etching was being used to create thin diaphragms that could convert pressure into an electrical signal. By 1970, selective anisotropic etching was being used for diaphragm formation, retaining a thick silicon rim to absorb package-induced stresses. Impurity- and electrochemically-based etch-stops soon emerged, and "bulk micromachining" came into its own.