Mohamed M. Atalla (Arabic: محمد عطاالله; August 4, 1924 – December 30, 2009) was an Egyptian-American engineer, physicist, cryptographer, inventor, and entrepreneur. He was an expert in semiconductors and helped shape modern electronics. He is best known for inventing the MOSFET (metal–oxide–semiconductor field-effect transistor, or MOS transistor) in 1959 with his colleague, Dawon Kahng. This invention, along with Atalla’s earlier work on surface passivation, greatly influenced the development of the electronics industry. He also founded the data security company Atalla Corporation (now Utimaco Atalla) in 1972. He received the Stuart Ballantine Medal (now the Benjamin Franklin Medal in physics) and was inducted into the National Inventors Hall of Fame for his contributions to semiconductor technology and data security.

Born in Port Said, Egypt, Atalla studied at Cairo University in Egypt and then at Purdue University in the United States. He joined Bell Labs in 1949 and later used the professional names "John" or "Martin" M. Atalla. At Bell Labs, he made important contributions to semiconductor technology, including developing the surface passivation process and demonstrating the MOSFET with Kahng in 1959. His work on the MOSFET was not recognized at first, leading him to leave Bell Labs. He then joined Hewlett-Packard (HP), founding its Semiconductor Lab in 1962 and HP Labs in 1966. Later, he worked at Fairchild Semiconductor, starting its Microwave & Optoelectronics division in 1969. His research at HP and Fairchild included studies on Schottky diodes, gallium arsenide (GaAs), gallium arsenide phosphide (GaAsP), indium arsenide (InAs), and light-emitting diode (LED) technologies. After leaving the semiconductor industry, he became an entrepreneur in cryptography and data security. In 1972, he founded Atalla Corporation and filed a patent for a remote Personal Identification Number (PIN) security system. In 1973, he created the first hardware security module, the "Atalla Box," which encrypted PIN and ATM messages, securing most ATM transactions worldwide. 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 (1924–1949)

Mohamed Mohamed Atalla was born in Port Said, Kingdom of Egypt. He studied at Cairo University in Egypt. He earned his Bachelor of Science degree there. He later moved to the United States to study mechanical engineering at Purdue University. At Purdue University, he received his master's degree (MSc) in 1947 and his doctorate (PhD) in 1949, both in mechanical engineering. His MSc thesis was titled "High Speed Flow in Square Diffusers." His PhD thesis was titled "High Speed Compressible Flow in Square Diffusers."

Bell Telephone Laboratories (1949–1962)

After finishing his PhD at Purdue University, Atalla began working at Bell Telephone Laboratories (BTL) in 1949. In 1950, he worked at Bell's New York City operations, where he studied problems related to the reliability of electromechanical relays and worked on circuit-switched telephone networks. When transistors became available, Atalla moved to the Murray Hill lab in 1956, where he led a small team researching transistors. Although he had a background in mechanical engineering and no formal training in physical chemistry, he quickly learned about these fields and became skilled in semiconductor physics. He studied the surface properties of silicon semiconductors and the use of silica as a protective layer for silicon devices. Later in his career, he used the pseudonyms "Martin" M. Atalla or "John" M. Atalla professionally.

Between 1956 and 1960, Atalla led a team of BTL researchers, including Eileen Tannenbaum, Edwin Joseph Scheibner, and Dawon Kahng. These researchers were new to BTL, and their team had no senior members. Senior management at BTL and AT&T did not take their work seriously at first because the team was made up of new recruits and because Atalla had a mechanical engineering background, unlike the physicists, chemists, and mathematicians who were usually respected. Despite this, Atalla and his team made major progress in semiconductor technology. Fairchild Semiconductor engineer Chih-Tang Sah called their work during 1956–1960 "the most important and significant technology advance" in silicon semiconductor technology.

Atalla’s early research focused on solving the problem of silicon surface states. At the time, the electrical conductivity of materials like germanium and silicon was limited by unstable quantum surface states, where electrons became trapped at the surface due to unsaturated bonds. This made it difficult for electricity to move reliably into the silicon layer. Because of this issue, germanium was the preferred material for transistors and other devices in the early semiconductor industry, as it allowed for better electrical movement.

Atalla made a breakthrough by developing the surface passivation process. This process makes a semiconductor surface inert, preventing it from changing properties when exposed to air or other materials. Atalla discovered that creating a thermally grown silicon dioxide (SiO₂) layer reduced the number of electronic states at the silicon surface. He found that SiO₂ films helped preserve the electrical characteristics of p–n junctions and protected them from damage caused by the surrounding environment. By coating silicon wafers with silicon oxide, Atalla enabled electricity to reliably reach the conducting silicon layer. His surface passivation method was a key step that made silicon integrated circuits widely used and became critical to the semiconductor industry. He also developed the method of thermal oxidation, a major advancement in silicon semiconductor technology.

Atalla first shared his findings in BTL memos in 1957. He later presented his work at an Electrochemical Society meeting in 1958. The semiconductor industry recognized the importance of his surface oxidation method, with RCA calling it a "milestone in the surface field." In 1959, Atalla and his colleagues refined the process and published their results. Fairchild Semiconductor engineer Chih-Tang Sah said Atalla’s surface passivation process "blazed the trail" for the development of silicon integrated circuits. Atalla’s technique was the basis for important inventions in 1959, including the MOSFET (MOS transistor) by Atalla and Dawon Kahng at Bell Labs, and the planar process by Jean Hoerni at Fairchild Semiconductor.

Building on his earlier research, Atalla developed the metal–oxide–semiconductor (MOS) process. He proposed creating a field effect transistor using metal-oxide-silicon, a concept first imagined in the 1920s and tested in the 1940s but not yet made into a working device. He assigned this task to Dawon Kahng, a scientist who had recently joined his team. This led to the invention of the MOSFET (metal–oxide–semiconductor field-effect transistor) by Atalla and Kahng in November 1959. They first demonstrated the MOSFET in early 1960. The MOSFET had advantages like high scalability, lower power use, and higher density compared to bipolar junction transistors, making it possible to build high-density integrated circuit (IC) chips.

In 1960, Atalla and Kahng created the first MOSFET with a gate oxide thickness of 100 nm and a gate length of 20 μm. In 1962, they developed a nanolayer-base metal–semiconductor junction (M–S junction) transistor. This device had a thin metallic layer between two semiconductor layers, with the metal acting as the base and the semiconductors as the emitter and collector. The device had low resistance and fast operation, making it suitable for high-frequency applications. They deposited gold (Au) thin films on n-type germanium (n-Ge) and used n-type silicon (n-Si) for the point contact. Atalla left BTL in 1962.

Atalla and Kahng continued their work on MOS technology, pioneering research on hot carrier devices that used what became known as a Schottky barrier. The Schottky diode, a type of diode theorized for years, was first practically created by Atalla and Kahng during 1960–1961. They published their findings in 1962, calling their device the "hot electron" triode structure with a semiconductor-metal emitter. It was one of the first metal-base transistors. The Schottky diode became widely used in mixer applications.

Hewlett-Packard (1962–1969)

In 1962, Atalla joined Hewlett-Packard, where he co-founded Hewlett-Packard and Associates (HP Associates). This group gave Hewlett-Packard the ability to work with solid-state technology. Atalla was the Director of Semiconductor Research at HP Associates and the first person to manage HP's Semiconductor Lab.

At HP Associates, Atalla continued research on Schottky diodes with Robert J. Archer. They developed a method to deposit metal films under high vacuum and created stable contacts using evaporation and sputtering techniques. They shared their findings in January 1963. This work led to a major improvement in metal–semiconductor junctions and Schottky barriers, solving many of the problems that made point-contact diodes difficult to produce and allowing the creation of practical Schottky diodes.

During the 1960s, Atalla started a program to study materials at the Semiconductor Lab. This program laid the foundation for technologies used in gallium arsenide (GaAs), gallium arsenide phosphide (GaAsP), and indium arsenide (InAs) devices. These devices became essential for HP's Microwave Division to build equipment that reached frequencies up to 20–40 GHz. This helped HP gain over 90% of the military communications market.

In 1966, Atalla helped create HP Labs. He led its solid-state division.

Fairchild Semiconductor (1969–1972)

In 1969, he left HP and joined Fairchild Semiconductor. He became the vice president and general manager of the Microwave & Optoelectronics division when it started in May 1969 and held this position until November 1971. During this time, he worked on light-emitting diodes (LEDs) and suggested they could be used for indicator lights and optical readers in 1971. He left Fairchild Semiconductor in 1972.

Atalla Corporation (1972–1990)

In 1972, he left the semiconductor industry and started a new career as a businessperson in data security and cryptography. That same year, he founded Atalla Technovation, which later became known as Atalla Corporation. The company focused on solving safety issues for banks and financial institutions.

He created the first hardware security module, called the "Atalla Box," a system that helps protect most ATM transactions today. He also played a key role in developing the personal identification number (PIN) system, which became a standard for identification in the banking industry.

In the early 1970s, his work led to the use of hardware security modules. The "Atalla Box" was a system that encrypted PINs and ATM messages and protected devices with a secret key that could not be guessed. He released the "Atalla Box" commercially in 1973 as the Identikey. This system was a card reader and customer identification tool that allowed banks to move from using passbooks to plastic cards. The Identikey included a card reader, two PIN keypads, a controller, and an electronic interface. It let customers enter a secret code, which the device converted into a different code for the teller. During a transaction, the customer’s account number was read by the card reader, replacing manual entry and reducing errors. This system replaced older methods like signature checks with a secure PIN system.

A major innovation in the Atalla Box was the key block, which allowed secure sharing of secret codes or PINs between banks. This method, called the Atalla Key Block (AKB), became the basis for cryptographic formats used in the Payment Card Industry Data Security Standard (PCI DSS) and American National Standards Institute (ANSI) standards.

Because Atalla’s technology was so successful, banks and credit card companies worked to create an international standard for PIN verification. His system was similar to the later IBM 3624. Atalla was an early competitor to IBM in the banking market and influenced IBM employees working on the Data Encryption Standard (DES). He is often called the "Father of the PIN" and a pioneer in information security technology.

By 1998, the Atalla Box protected over 90% of all ATM networks in use, and by 2006, it secured 85% of all ATM transactions worldwide. As of 2014, Atalla products still secured most ATM transactions globally.

In 1972, Atalla filed a U.S. patent (number 3,938,091) for a remote PIN verification system. This system used encryption to protect personal ID information sent over telephone networks to a remote location for verification. It was an early step toward telephone banking, Internet security, and e-commerce.

At a conference in January 1976, Atalla announced an upgrade to the Identikey system called the Interchange Identikey. This version could handle online transactions and improve network security. It was designed to support online banking and was compatible with different switching networks. The device could reset itself to one of 64,000 secure algorithms based on card data. The Interchange Identikey was released in March 1976. It was one of the first products made to handle online transactions, along with products from Bunker Ramo Corporation presented at the same conference. In 1979, Atalla introduced the first network security processor (NSP).

In 1987, Atalla Corporation merged with Tandem Computers. Atalla retired in 1990.

As of 2013, Atalla products protected 250 million card transactions every day.

TriStrata Security (1993–1999)

In the early 1990s, several leaders from major banks asked him to create security systems for the Internet era. They were concerned that without progress in computer and network security, it would not be possible to build a reliable system for online business. After receiving a request from William Zuendt, the former president of Wells Fargo Bank, in 1993, Atalla started working on a new Internet security technology. This technology enabled companies to send secure files, emails, and digital videos and music over the Internet.

Because of this work, he started a company called TriStrata Security in 1996. Unlike most traditional security systems at the time, which protected an entire company’s network by building barriers around it, TriStrata used a different method. Its system placed a secure, encrypted container around individual pieces of information, such as a document, a customer list, or an email. This container could only be opened with a digital key, allowing companies to control which users could access the information and what permissions they had. At the time, this method was seen as a new way to protect business data.

Later years and death (2000–2009)

Atalla was the chairman of A4 System in 2003. He lived in Atherton, California. Atalla died on December 30, 2009, in Atherton, California.

Awards and honors

In 1975, Atalla received the Stuart Ballantine Medal, which is now called the Benjamin Franklin Medal in physics, at the Franklin Institute Awards. He was honored for his important work in silicon semiconductor technology and for inventing the MOSFET. In 2003, Purdue University gave Atalla a Distinguished Alumnus doctorate. In 2009, he was inducted into the National Inventors Hall of Fame for his important contributions to semiconductor technology and data security. He was known as one of the "Sultans of Silicon" along with other semiconductor pioneers. In 2014, the 1959 invention of the MOSFET was added to the IEEE's list of important milestones in electronics. In 2015, Atalla was inducted into the IT History Society's IT Honor Roll for his important contributions to information technology.