Mohamed M. Atalla
Mohamed M. Atalla was an Egyptian-American engineer, physicist, cryptographer, inventor and entrepreneur. He was a semiconductor pioneer who made important contributions to modern electronics. He is best known for inventing, along with his colleague Dawon Kahng, the MOSFET in 1959, which along with Atalla's earlier surface passivation processes, had a significant impact on the development of the electronics industry. He is also known as the founder of the data security company Atalla Corporation, founded in 1972. He received the Stuart Ballantine Medal and was inducted into the National Inventors Hall of Fame for his important contributions to semiconductor technology as well as data security.
Born in Port Said, Egypt, he was educated at Cairo University in Egypt and then Purdue University in the United States, before joining Bell Labs in 1949 and later adopting the more anglicized "John" or "Martin" M. Atalla as professional names. He made several important contributions to semiconductor technology at Bell Labs, including his development of the surface passivation process and his demonstration of the MOSFET with Kahng in 1959.
His work on MOSFET was initially overlooked at Bell, which led to his resignation from Bell and joining Hewlett-Packard, founding its Semiconductor Lab in 1962 and then HP Labs in 1966, before leaving to join Fairchild Semiconductor, founding its Microwave & Optoelectronics division in 1969. His work at HP and Fairchild included research on Schottky diode, gallium arsenide, gallium arsenide phosphide, indium arsenide and light-emitting diode technologies. He later left the semiconductor industry, and became an entrepreneur in cryptography and data security. In 1972, he founded Atalla Corporation, and filed a patent for a remote Personal Identification Number security system. In 1973, he released the first hardware security module, the "Atalla Box", which encrypted PIN and ATM messages, and went on to secure the majority of the world's ATM transactions. He later founded the Internet security company TriStrata Security in the 1990s. He died in Atherton, California, on December 30, 2009.
Early life and education (19241949)
Mohamed Mohamed Atalla was born in Port Said, Kingdom of Egypt. He studied at Cairo University in Egypt, where he received his Bachelor of Science degree. He later moved to the United States to study mechanical engineering at Purdue University. There, he received his master's degree in 1947 and his doctorate in 1949, both in mechanical engineering. His MSc thesis was titled "High Speed Flow in Square Diffusers" and his PhD thesis was titled "High Speed Compressible Flow in Square Diffusers".Bell Telephone Laboratories (19491962)
After completing his PhD at Purdue University, Atalla was employed at Bell Telephone Laboratories in 1949. In 1950, he began working at Bell's New York City operations, where he worked on problems related to the reliability of electromechanical relays, and worked on circuit-switched telephone networks. With the emergence of transistors, Atalla was moved to the Murray Hill lab, where he began leading a small transistor research team in 1956. Despite coming from a mechanical engineering background and having no formal education in physical chemistry, he proved himself to be a quick learner in physical chemistry and semiconductor physics, eventually demonstrating a high level of skill in these fields. He researched, among other things, the surface properties of silicon semiconductors and the use of silica as a protective layer of silicon semiconductor devices. He eventually adopted the pseudonyms "Martin" M. Atalla or "John" M. Atalla for his professional career.Between 1956 and 1960, Atalla led a small team of several BTL researchers, including Eileen Tannenbaum, Edwin Joseph Scheibner and Dawon Kahng. They were new recruits at BTL, like himself, with no senior researchers on the team. Their work was initially not taken seriously by senior management at BTL and its owner AT&T, due to the team consisting of new recruits, and due to the team leader Atalla himself coming from a mechanical engineering background, in contrast to the physicists, physical chemists and mathematicians who were taken more seriously, despite Atalla demonstrating advanced skills in physical chemistry and semiconductor physics.
Despite working mostly on their own, Atalla and his team made significant advances in semiconductor technology. According to Fairchild Semiconductor engineer Chih-Tang Sah, the work of Atalla and his team during 19561960 was "the most important and significant technology advance" in silicon semiconductor technology.
Surface passivation by thermal oxidation
An initial focus of Atalla's research was to solve the problem of silicon surface states. At the time, the electrical conductivity of semiconductor materials such as germanium and silicon were limited by unstable quantum surface states, where electrons are trapped at the surface, due to dangling bonds that occur because unsaturated bonds are present at the surface. This prevented electricity from reliably penetrating the surface to reach the semiconducting silicon layer. Due to the surface state problem, germanium was the dominant semiconductor material of choice for transistors and other semiconductor devices in the early semiconductor industry, as germanium was capable of higher carrier mobility.He made a breakthrough with his development of the surface passivation process. This is the process by which a semiconductor surface is rendered inert, and does not change semiconductor properties as a result of interaction with air or other materials in contact with the surface or edge of the crystal. The surface passivation process was first developed by Atalla in the late 1950s. He discovered that the formation of a thermally grown silicon dioxide layer greatly reduced the concentration of electronic states at the silicon surface, and discovered the important quality of SiO2 films to preserve the electrical characteristics of p–n junctions and prevent these electrical characteristics from deteriorating by the gaseous ambient environment. He found that silicon oxide layers could be used to electrically stabilize silicon surfaces. He developed the surface passivation process, a new method of semiconductor device fabrication that involves coating a silicon wafer with an insulating layer of silicon oxide so that electricity could reliably penetrate to the conducting silicon below. By growing a layer of silicon dioxide on top of a silicon wafer, Atalla was able to overcome the surface states that prevented electricity from reaching the semiconducting layer. His surface passivation method was a critical step that made possible the ubiquity of silicon integrated circuits, and later became critical to the semiconductor industry. For the surface passivation process, he developed the method of thermal oxidation, which was a breakthrough in silicon semiconductor technology.
Atalla first published his findings in BTL memos during 1957, before presenting his work at an Electrochemical Society meeting in 1958, the Radio Engineers' Semiconductor Device Research Conference. The semiconductor industry saw the potential significance of Atalla's surface oxidation method, with RCA calling it a "milestone in the surface field." The same year, he made further refinements to the process with his colleagues Eileen Tannenbaum and Edwin Joseph Scheibner, before they published their results in May 1959. According to Fairchild Semiconductor engineer Chih-Tang Sah, the surface passivation process developed by Atalla and his team "blazed the trail" that led to the development of the silicon integrated circuit. Atalla's silicon transistor passivation technique by thermal oxide was the basis for several important inventions in 1959: the MOSFET by Atalla and Dawon Kahng at Bell Labs, the planar process by Jean Hoerni at Fairchild Semiconductor.