Shared Fabs Shared Companies How Linear and Mos Digital Commercialization Grew Together

# Shared Fabs, Shared Companies: How Linear and MOS Digital Commercialization Grew Together

## 1. The Same Companies, Spanning Both Product Categories

Fairchild Semiconductor is the clearest single example of this series' connective argument: the same company whose analog group employed Bob Widlar through the uA702, uA709, and the lineage leading to the 741 also employed engineers who left to found General Microelectronics and, later, Intel, carrying MOS process knowledge outward from the same campus where linear amplifier design was advancing in parallel.

This was not a coincidence of geography alone. Both product lines depended on the same underlying era of bipolar and MOS process equipment — diffusion furnaces, photolithography steps, metallization lines — maturing together through the 1960s, and a company's investment in better process control for one product line tended to improve the other, because contamination control, oxide quality, and photomasking precision mattered to a calculator-chip yield problem and to an amplifier's matching precision alike.

## 2. One Growth Curve, Two Product Categories

The industry's overall growth curve through the late 1960s and into the 1970s was fueled by both stories at once: MOS digital logic proving that dense, cheap logic had a real commercial market, and linear ICs proving that the same monolithic-integration argument worked for an entirely different kind of circuit. Investors, equipment suppliers, and the broader semiconductor industry's growth projections through this period counted both as part of the same expanding integrated-circuit market, even though the two product categories solved genuinely different engineering problems, as the earlier steps in Part B made explicit.