The invention of the charged coupled device (CCD) almost ten years ago and the utility of the charge transfer device (C'I'D) in general has made development of mosaic focal planes possible. The nature of the metal-oxide semiconductor (MOS) manufacturing processes utilized in most CTlls posed special requirements for material, process control, and device evaluation which have been and still are, the object of intensive technology development programs in the past several years. Achieving the long-standing goals of high-volume, low-cost production potential of the technology for mosaic focal planes is still in the future. The degree of achievement of these goals will depend a great deal upon adoption of some standardization of device architecture, operating conditions, test parameters, and evaluations techniques. Production of these devices will require capital investments for dedicated specialized facilities necessary to achieve volume production.