Classic Semiconductor Devices-Point contact Through HSI; Solving Easy Problems: Part II

This conference was the first technical forum to hear of the transistor. Although subsequent advances were shared with other conferences, many of them its offspring, the Device Research Conference was the leader for classic semiconductor devices, from the point contact transistor and the photodiode to the farthest limits of integration and the charge-coupled area imager. Its spirit of sharing knowledge so as to achieve shared and rapid technical advance permeated the field for many years. The openness advocated and practiced by Jack A. Morton and the Bell Laboratories was followed by breath-taking technology changes, a majority of them from Bell Laboratories. Structures and theory went from basic junction to space charge layer widening to high level injection to the drift transistor, this conceived before its time by a young German theorist at Darmstadt. The heterojunction and ion implanted structures were proposed. Germanium grown junctions were followed by germanium alloy transistors, a technology still practiced commercially here at Boston. The surface barrier transistor was followed by the micro-alloy transistor. Diffused transistors appeared in germanium and silicon and the diffusion approach was grafted onto existing manufactures of grown junction devices and alloy devices, with the microalloy diffused transistor (MADT) enjoying a brief moment in the spotlight of performance before being washed away by the use of epitaxial substrates in mesa and planar devices. Then the silicon integrated circuit with its reverse bias insulation, integral Si02 insulation, and adherent aluminum wiring appeared and the world was transformed again. At the same time as epitaxy and the integrated circuit, the MOS transistor came out. rapidly followed (in consequence of prodigious efforts) by CMOS circuits. Then. very late, long after a transit time semiconductor device was proven impractical, the charge-coupled device emerged and to dominate the photosensing world. In all this. processing was key, with single crystal growth most fundamental. diffusion ubiquitous and unavoidable. and oxide masking and photolithography astonishing in their capability for geometric down-scaling. Ion implantation came to improve control and to permit new subtleties of structure. Nature is in such balance that the properties of silicon are as desirable as they seem improbable. Energy gap, impurity solubilities and diffusion constants. carrier mobilities and lifetimes, surface state densities let wild dreams become realities.