Mostek Corporation was a semiconductor integrated circuit manufacturer, founded in 1969 by L. J. Sevin, Louay E. Sharif, Richard L. Petritz and other ex-employees of Texas Instruments. At its peak in the late 1970s, Mostek held an 85% market share of the dynamic random-access memory (DRAM) memory chip market worldwide, until being eclipsed by lower-priced Japanese DRAM manufacturers who were accused of dumping memory on the market. In 1979, soon after its market peak, Mostek was purchased by United Technologies Corporation for . In 1985, after several years of red ink and declining market share, UTC closed Mostek completely and sold it for to the French electronics firm Thomson-CSF, which later spun it off into STMicroelectronics. Early Products Mostek's first contract was from Burroughs, a $400 contract for circuit design. Initially Mostek products were manufactured in Worcester, Massachusetts in cooperation with Sprague Electric, however by 1974 most of its manufacturing was done at their headquarters in Carrollton, Texas. The first design to be produced was the MK1001, a simple barrel shifter chip made using an aluminum-gate PMOS process. This was followed by a 1K DRAM, the MK4006, designed by Vern McKinney, that was manufactured in their Carrollton facility. Mostek had been working with Sprague Electric to develop the ion implantation process which provided much better control of doping profiles, especially in lowering enhancement-mode transistor threshold voltage and providing depletion-load transistors. Using ion implantation, Mostek became an early leader in MOS manufacturing technology, while their competition was still mostly using the older bipolar technology. The resulting increased speed and lower cost of the MK4006 memory chip made it the runaway favorite to IBM and other mainframe and minicomputer manufacturers (cf. BUNCH, Digital Equipment Corporation). In 1970 Busicom, a Japanese adding machine manufacturer, approached Intel and Mostek with a proposal to introduce a new electronic calculator line. Intel responded first, providing them with the Intel 4004, which they used in a line of desktop calculators. Mostek's device took longer to develop but was the world's first single chip calculator, the MK6010, used for the Busicom LE-120A which went on the market in 1971 and was the smallest calculator available for some time. Hewlett-Packard also contracted with Mostek for design and production of chips for their HP-35 and HP-45 calculators. World leader in DRAM Mostek co-founder Robert Proebsting invented DRAM address multiplexing with the MK4096 4096 X 1 bit DRAM introduced in 1973.