Sandy Barnes


Oral History – Sandy Barnes (Continued)




This scan shows segments of the patent awarded to Sandy Barnes in 1956 that described the technology required for the manufacture of silicon point contact diodes – the technology outlined in this patent is quite elegant and led to a substantial business success.  By combining this unique technology with the previously discussed glass encapsulation process, Hughes became a dominant semiconductor manufacturer in the late 1950s and maintained this leadership position for many years. 


Go To Barnes Oral History, Page 5




Oral History – Sandy Barnes (Continued)


Let’s discuss the Hughes diode program.  How did this start and what was your involvement?


Patent (2,693,555) was filed in 1951 by myself, North and Roach -  it was related to the development of a glass sealed package to encapsulate germanium crystal devices. The crystal and a lead wire are integrated into a single vitreous envelope using the techniques described in this patent.  The widespread use of the techniques described in this and other related patents allowed Hughes to license all semiconductor companies, including IBM and Texas Instruments, to use the glass diode package.  The design of this package, which was initially known as the DO-5 package, eventually became the worldwide standard for hermetic diode packages.  In prior art, both germanium and silicon semiconductors had been used successfully for point-contact diodes.  It was recognized that silicon has many advantages over germanium, particularly high temperature characteristics. Several obstacles had to be overcome, however, such as the difficulty in making a low resistance contact to the silicon, the inherent tendency of silicon to form an extremely hard and stable oxide, and the relatively high melting point of silicon and its brittleness.  My patent (2,736,847), filed in 1954, directly addressed these difficulties – I presented a paper “A Silicon Junction Diode Sealed in Glass” at the 1954 AIEE in NY.  Large scale manufacturing of these diodes began immediately thereafter at Hughes. 


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