In 1959, metal–oxide–semiconductor field-effect transistor (MOSFET) was invented by Dawon Kahng and Martin M. (John) Atalla at Bell Labs. Julius Edgar Lilienfeld had already patented the basic principle of this kind of transistor in 1925. But later the Bell Labs edition was allocated the name bipolar junction transistor, or merely junction transistor, and design of Lilienfeld came to be identified as field effect transistor. Later, Jean Hoerni found that Silicon dioxide (SiO2) should be used to passivate the surface edges of p-n junctions, and it was demonstrated in his patent application in May 1959. This planar structure led Robert Noyce to integrate a variety of devices, such as diodes and transistors. Their interference was avoided by separating
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Earlier, typical MOSFET channel lengths were in the range of several micrometers, but modern integrated circuits have started integrating MOSFETs with channel lengths of tens of nanometers. The difficulties with decreasing the size of the MOSFET have always been related with the fabrication procedure of the semiconductor device, the need for using very low voltages, and with inferior electrical characteristics. These obstacles have been making it necessary for redesigning of circuits and modernization of the fabrication process. Smaller MOSFETs are more desirable for several reasons. The main reason to reduce transistors size is to pack as many devices as possible in a given chip area. The outcome of this change is a chip with the identical functionality in a smaller area, or chips with additional functionality in the same …show more content…
Hence, smaller ICs permit more chips per wafer that helps in reducing the cost per chip. Over the past many years, the quantity of transistors produced per chip has increased by almost double every after approximately 2 years every time a new technology node is set up. Gordon Moore was the first person to notice this enhancement in transistor density in 1965 and therefore it is frequently referred to as Moore's law. He had predicted that for every memory chip and microprocessor unit of the new generation, the device size would decrease by 33 percent, the chip size would increase by 50 percent, and the number of components on a chip would quadruple every three years (Moore, 1965).
1.3 Limitations of MOSFET Scaling
Fabricating MOSFETs with channel lengths much smaller than a micrometer has been a continuous challenge, and the difficulties of semiconductor device fabrication have always been a limiting factor in modernizing integrated circuit technology. Over last few years, the minute size of the MOSFET, under a few tens of nanometers, has led to operational problems. Some of these problems have been summarized below:
1.3.1 Higher Sub-threshold
Earlier, typical MOSFET channel lengths were in the range of several micrometers, but modern integrated circuits have started integrating MOSFETs with channel lengths of tens of nanometers. The difficulties with decreasing the size of the MOSFET have always been related with the fabrication procedure of the semiconductor device, the need for using very low voltages, and with inferior electrical characteristics. These obstacles have been making it necessary for redesigning of circuits and modernization of the fabrication process. Smaller MOSFETs are more desirable for several reasons. The main reason to reduce transistors size is to pack as many devices as possible in a given chip area. The outcome of this change is a chip with the identical functionality in a smaller area, or chips with additional functionality in the same …show more content…
Hence, smaller ICs permit more chips per wafer that helps in reducing the cost per chip. Over the past many years, the quantity of transistors produced per chip has increased by almost double every after approximately 2 years every time a new technology node is set up. Gordon Moore was the first person to notice this enhancement in transistor density in 1965 and therefore it is frequently referred to as Moore's law. He had predicted that for every memory chip and microprocessor unit of the new generation, the device size would decrease by 33 percent, the chip size would increase by 50 percent, and the number of components on a chip would quadruple every three years (Moore, 1965).
1.3 Limitations of MOSFET Scaling
Fabricating MOSFETs with channel lengths much smaller than a micrometer has been a continuous challenge, and the difficulties of semiconductor device fabrication have always been a limiting factor in modernizing integrated circuit technology. Over last few years, the minute size of the MOSFET, under a few tens of nanometers, has led to operational problems. Some of these problems have been summarized below:
1.3.1 Higher Sub-threshold