After completing his PhD at
Purdue University, Atalla was employed at
Bell Telephone Laboratories (BTL) 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. He researched, among other things, the surface properties of
silicon semiconductors and the use of
silica as a protective layer of silicon
semiconductor devices. 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. 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. He made a breakthrough with his development of the
surface passivation process. He discovered that the formation of a
thermally grown
silicon dioxide (SiO2) layer greatly reduced the concentration of
electronic states at the silicon surface, 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. 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. was the basis for several important inventions in 1959: the
MOSFET (MOS transistor) by Atalla and
Dawon Kahng at Bell Labs, the
planar process by
Jean Hoerni at
Fairchild Semiconductor.
MOSFET (MOS transistor) was invented by Atalla with his colleague
Dawon Kahng in 1959, based on Atalla's earlier
surface passivation and
thermal oxidation processes. Building on his earlier pioneering research on the surface passivation and thermal oxidation processes, in November 1959. With its
high scalability, and much lower power consumption and higher density than
bipolar junction transistors, the MOSFET made it possible to build
high-density integrated circuit (IC) chips.
Nanolayer transistor In 1960, Atalla and Kahng
fabricated the first MOSFET with a
gate oxide thickness of
100 nm, along with a
gate length of
20μm. In 1962, Atalla and Kahng fabricated a
nanolayer-base
metal–semiconductor junction (M–S junction) transistor. This device has a metallic layer with
nanometric thickness sandwiched between two semiconducting layers, with the metal forming the base and the semiconductors forming the emitter and collector. With its low resistance and short transit times in the thin metallic nanolayer base, the device was capable of high operation
frequency compared to
bipolar transistors. Their pioneering work involved depositing metal layers (the base) on top of
single crystal semiconductor substrates (the collector), with the emitter being a
crystalline semiconductor piece with a top or a blunt corner pressed against the metallic layer (the point contact). They deposited
gold (Au)
thin films with a thickness of
10 nm on
n-type germanium (n-Ge), while the point contact was n-type silicon (n-Si). Atalla resigned from BTL in 1962. The
Schottky diode, also known as the Schottky-barrier diode, was theorized for years, but was first practically realized as a result of the work of Atalla and Kahng during 19601961. They published their results in 1962 and called their device the "hot electron" triode structure with semiconductor-metal emitter. It was one of the first
metal-base transistors. The Schottky diode went on to assume a prominent role in
mixer applications. == Hewlett-Packard (19621969) ==