Donald L. Klein is the son of a Hungarian father and a Hungarian-American mother, who grew up in Brooklyn, New York. With his childhood friend, Neil Wotherspoon, Klein developed an early passion for chemistry, electronics, and amateur radio, interests that would follow him throughout his life and career. At Brooklyn Technical High School, he discovered an additional passion for metallurgy. He completed his undergraduate degree in chemistry at Polytechnic Institute of Brooklyn (now Polytechnic Institute of New York University), then found a job in the semiconductor industry to support his new wife (who also received a degree in chemistry). After working for a couple of years, he pursued a graduate degree at the University of Connecticut to study photochemistry under Dr. Roland Ward. Klein was recruited to work for Bell Laboratories, and began working on the production of semiconductors. His group was involved in involved in developing etching techniques for semiconductors and methods to prevent different types of contamination in semiconductor production. In February 1966, Klein was in charge of a brainstorming session with several other Bell scientists to design a better process for building FET devices. They first identified the problems with current models and processes; out of that meeting came the idea of using a heavily doped polycrystalline silicon layer as the gate of an FET. The gate was to be supported on dual layers of a silicon nitride and silicon dioxide serving as the gate insulator. Using the FET as a model for integrated circuits, they fabricated and characterized hundreds of FET devices at high yield that exhibited close electrical tolerances. Klein and his colleagues published several papers on their new technology, and applied for patents on their process, though Bell's management was slow to appreciate the breakthrough its scientists had made. After a restructuring, Klein left Bell to work for IBM. The rest of the industry, however, was quick to adopt and improve the silicon gate technology. There were legal disputes throughout the 1970s, but by that time Klein was at IBM developing photoresist technologies and more efficient processes for manufacturing electronic packaging.