FORTY-YEAR OLD PLASTIC TRANSISTORS

By Howard Dicken
 Reprinted from SMEC 'Vintage Electrics' Vol. #2, 1990 -C. SMECC 2002

 
How good is plastic encapsulation? After approximately 40 years, at least one device is still functional but degraded.

The trace below is of a Bell Labs Ge, grown junction, NPN transistor code number 1752, from the K.D. Smith Collection at the Southwest Museum of Electricity and Communications. It was processed and tested in the 1951 time period. After lead attachment, the Ge bar was potted in plastic and painted black.

The original lab measurements are written on the paper envelope containing the part, illustrated at right. The following are the present values:

Alpha = .86 This is a beta of 6. The original measured beta was 75. This is the most significant parameter change. It was probably caused by contamination or surface leakage at the unpassivated grown junctions.

VERT: 2 VOLTS/DIV HORZ: 0.5 MA/DIV

STEP: 0.2 MA/STEP

rb = 1400 ohms

re = 40 ohms

Ico = 240 uA

BVebo = 50

BVcbo = 45 and still sloppy

With a forgiving circuit design which would accept a range of beta, this part would still be functional.

There is another aspect to this device. Some of the personnel on this project migrated to TI, continuing the grown junction transistor work and eventually produced the first silicon devices in large quantities.

EXPERIENCE:

Prior to forming DM Data Inc., Mr. Dicken was president of ICE where he directed the activities of the corporate staff and the five divisions of ICE. He also developed new business ventures for ICE and established goals and business objectives. Mr. Dicken also was active in general consulting and managed over 250 client projects.

Prior to joining ICE, Mr. Dicken was head of the Integrated Circuit Pilot Production Line at Motorola where he participated in some of the initial integrated circuit component research and development. Previous experience includes design and development work at Sandia Corporation. other background includes special training in the U.S. Army Signal Corps and assignments as a Special Weapons Assembly Officer.

EDUCATION: Mr. Dicken received a B.S.E.E. at Iowa State College in 1956 and an M.S.E.E. at Iowa State University in 1961. In addition, he has attended various management training programs and other postgraduate courses.

PUBLICATIONS: Mr. Dicken has published numerous papers and articles for magazines and technical journals, specializing in the integrated circuit design and assembly areas.

MEMBERSHIPS: Mr. Dicken is a member of the Tau Beta Pi and Eta Kappa Nu.