Type his name into Google, and only five or six items come up: a Wiki entry, a couple of memorial pages on the Southwest Museum of Engineering, Communications and Computation Web site (www.smecc.org), thanks to Ed Sharpe, director and lead archivist, and several obituaries.
On the contrary, go through any book, technical journal, or research paper that deals with the theory and/or behavior of bipolar transistors, and his name figures prominently. Credited with several accomplishments, he is most notably associated with his discovery of what is now known as the Early effect in bipolar transistors (Fig. 2).
Simply stated, the Early effect is the reduction of the width of the base charge region in a bipolar transistor due to the widening of the base-collector junction with increasing base-collector voltage. This effect is observable as a slight increase in collector current in the saturation region.
In The Beginning
James Early was born July 25, 1922, the second of nine children, in Syracuse, N.Y. Before entering electronics, oddly enough, he first received a bachelor of science degree in pulp and paper manufacturing in 1943 from the New York State College of Forestry, Syracuse.
It wasn’t until after a stint in the army from 1943 to 1945 that he entered Ohio State University as both a graduate student and instructor in electrical engineering. He received a master of science degree in magnetron resonances in 1948 and forged ahead to a PhD in anisotropic dielectric waveguides in 1951.
Also in 1951, Early went to work at Bell Telephone Laboratories in Murray Hill, N.J., as a member of the technical staff under the supervision of Kenneth D. Smith and under the auspices of the ever popular Nobel Prize winner William Shockley. During his days there, he discovered the effect that bears his name while working on grown and alloy germanium transistors, germanium diffused base transistors, and silicon diffused transistors.
He also played a role in designing solar cells for the Telstar satellite as well as integrated circuits. In summary, Early spent 18 fruitful years at Bell Labs, the last seven as lab director.
Early migrated in 1969 to Palo Alto, Calif., to become vice president of research and development at Fairchild Semiconductor. Originally created in 1957 by a number of scientists William Shockley recruited from the east coast, Fairchild Semiconductor is believed to have been the launching pad for a number of other notable startups of the day, i.e., Intel, National Semiconductor, and Advanced Micro Devices.
At Fairchild, Early was responsible for processes as well as devices. In addition to moving the company into the use of ion beam implantation, whole wafer lithography, electron beam mask making, and charge-coupled device (CCD) design, he developed bipolar memories, emitter-coupled logic (ECL) circuit technology, CMOS without guard rings, and numerous other CCD projects.
Early stayed with Fairchild until his retirement in 1986, with 14 patents and numerous published papers, the fruits of his labors. Also during that period he participated in the Advisory Group on Electron Devices, Department of Defense, for 20 years until 1982.
Also, Early was a Fellow of the American Association for the Advancement of Science (AAAS) and a member of the American Physical Society (APS). He received the Texnikoi and Distinguished Alumnus Awards from Ohio State University and the J.J. Ebers Award from the IEEE Electron Devices Society. He served IEEE and its IRE predecessor on the first transistor standardization committees and was active in the annual device research conferences as well.
Early passed away at the age of 81 on January 12, 2004, at the veterans’ hospital in Palo Alto. The cause of death was complications from asthma, which he suffered from since childhood. On a lighter note, showing that he was a true believer in the engineering ethic that if something serves no function then get rid of it, legend has it that upon his retirement in 1986 he burned all of his neckties. Now that’s progress!
Looking Closer At The Early Effect
In the world of transistors and semiconductors in general, Early will be most remembered for his identification and description of the variations in width of a bipolar transistor’s base and collector under certain voltage conditions. More exactly described, while working at Bell Labs, he observed and detailed variations in the width of the base junction in a bipolar junction transistor that result from voltage variations in the base-to-collector junction.
Early pointed out that as the reverse bias across the base-collector junction rises, the base-collector depletion width increases, which in turn narrows the width of the neutral zone in the base junction. Most appropriately, this phenomenon is dubbed the Early Effect.
“A variation of the base-collector voltage results in a variation of the quasi-neutral width in the base,” wrote University of Colorado professor Bart Van Zeghbroeck in chapter five of his work, Principles of Semiconductor Devices. “The gradient of the minority-carrier density in the base therefore changes, yielding an increased collector current as the collector-base current is increased. This effect is referred to as the Early effect.”
Narrowing of the base width incurs an increase in the charge across the base as well as an increase in minority charge carriers. As a result, collector current and voltage both increase.
As per Zeghbroeck, the Early effect is observed as an increase in the collector current with increasing collector-emitter voltage. The Early voltage (VA) is derived by drawing a line tangential to the transistor I-V characteristic at the point of interest. The VA equals the horizontal distance between the point chosen on the I-V characteristics and the intersection between the tangential line and the horizontal axis.
A Personal Note
“He was always generous with his advice. And you know, in all the time I knew him, he never gave me bad advice,” said Ed Sharpe of the Southwest Museum of Engineering. He and Early met in the early 1990s to collaborate on an archiving project of epic proportions.
Sharpe inherited an Ark’s load of semiconductors from Kenneth D. Smith, Early’s first supervisor at Bell Labs. Most of the devices were of mysterious and unknown origins, and Early gladly volunteered to help identify them for the museum.
“He made two trips to the museum to assist in identifying many devices that often appeared as a unmarked glob with wires sticking out of them! Jim pointed to two very large clugy metallic semiconductor devices and stated, ‘Would you like to know what happened to the third one?’” Sharpe said.
“With a wry smile he went on to tell me about ‘captured’ USSR technology being sent to Bell Labs for evaluation by the government. The third unit that was not present had been autopsied to determine the level of the USSR transistor development,” Sharpe explained.
“One of Jim’s passions was getting people into IEEE,” Sharpe also said. “He sponsored me in as well as many budding engineers.”
Another good habit, Early would often introduce himself to young engineering students and watch their reactions upon learning who he was.
“There was one time he and his wife Mary Agnes were in a luncheonette and Jim overheard some college students discussing semiconductors in the booth behind him. He turned around, introduced himself, and proceeded to give his insights to their conversation,” Sharpe said. “Jim related how it was fun to see their jaws drop when they learned who they were speaking to.”
One thread that runs through almost everything written about Early is his commitment to family. No matter how involved he got in his work, he always made time to take his family on trips and vacations, as well as address their day-to-day needs and crises.
“We’d be working and he’d get a phone call from one of his kids. He’d interrupt whatever we were doing to tend to whatever they needed,” Sharpe said.
Early’s other passion was bicycling. He rode his bike to work every day until retiring. Mentioned earlier, his anti-passion, if you will, was for neckties.
So why did Early make a leap from a degree in pulp and paper manufacturing to electronics engineering?
“Ohio had a large paper manufacturing business and there were jobs available in that field,” Sharpe said. “World War II came along and after U.S. Army service at Ohio State University and the Manhattan Engineer District, Oak Ridge, Tenn., Jim found a new calling in the field of electronics, a field that was exploding after all the spinoffs after the war.”