Serendipity and HCL

This contribution from Ian McWalter of CMC

In the 1970s there was a company in Ottawa called Microsystems International, essentially a research wing for Northern Telecom (Nortel for anyone under 30). They had great technical successes but were eventually shut down... this closure and the severance pay that came with it led to a tech boom in Ottawa a decade later and still today.

Semiconductors were plagued by contaminating mobile ions like sodium (Na+) which were especially problematic in the growth of transistor gate oxide. To try to reduce contamination HydroChloric gas.(HCL) was used to flush the quartz tubes in which the gate growth (oxidation) was carried out. One night a technician forgot to turn off the HCl source during a gate oxide growth and the result was spectacularly good transistor performance! Within a short time every foundry used HCl during gate oxidation,

The paper is here http://jes.ecsdl.org/content/119/3/388.abstract

and the patent is here http://www.google.com/patents/US3692571