![]() ![]() ![]() With the help of nanotechnology, Moore’s Law may continue far into the future. ![]() Even with today's process technology providing what was formerly considered impossible numbers of gates on a single chip, gate counts remain one of the most important overall factors in the end price of a chip. Transistors have come a long way since their early days, allowing computers to shrink from the size of cars to the size of a wrist watch. In microprocessor design, gate count refers to the number of gates build with transistor and other electronic devices, that are needed to implement a design. (To read lots more detail about these new innovations, check out Hayley Bennett’s article, “ The search for the new silicon.” ) Others are changing the material used for the gate from silicon dioxide to hafnium dioxide nanorods. For example, some researchers are exploring ways to use 2D materials like molybdenum disulfide to improve the transistor channel. If the transistor’s control of on and off no longer exists, it cannot speak binary, and your processor is useless!īut in addition to causing problems with silicon transistors, nano-scale effects have the potential to open up lots of possibilities for new transistor technology. In the context of our transistor, this means the gate cannot prevent the flow of electrons through the channel. Electron tunneling is like teleportation: when materials are really thin (less than a nanometer), the electrons can move right through them. The quantum effect that alters the performance of nanotransistors is called electron tunneling. At such small sizes, the classical behaviors of matter and energy are different. However, as transistors reach the nanoscale, we enter into the world of quantum mechanics. Moore’s Law from 1965, which predicted an exponential increase in the number of transistors that can fit on a circuit, has generally proved to be true. The fact that you can check your email, play a game, and listen to music on your phone all at the same time is largely a result of nanotechnology helping to shrink transistors! This means the device will be faster and can execute more tasks. The more transistors in a device, the more combinations of binary codes it can process. The number of transistors that can fit in an IC is called a transistor count. Multiple transistors are combined into what is called an integrated circuit (IC). This on and off status translates perfectly to the binary language of computers, which is composed of different combinations of ones and zeros that tell the device what to do. 2 Once the silicon is doped, the movement of electrons can either be turned on (allowing the flow of electrons), or off (stopping the flow of electrons), using a voltage. Alone, silicon cannot control the movement of electrons, so an impurity must be added in a process called doping, typically with boron, phosphorus, selenium or germanium. The most popular semiconducting material for making computer transistors is silicon (hence the name Silicon Valley). The ANSI symbol for the NAND gate is a standard AND gate with an inversion bubble connected.The University of Manchester Atlas in 1963: one of the world’s first supercomputers (image by Ian MacCallum ) ![]() For more information see logic gate symbols. There are three symbols for NAND gates: the MIL/ ANSI symbol, the IEC symbol and the deprecated DIN symbol sometimes found on old schematics. NAND gates with two or more inputs are available as integrated circuits in transistor-transistor logic, CMOS, and other logic families. One way of expressing A NAND B is A ∧ B ¯. , a n) is logically equivalent to NOT( a 1 AND a 2 AND. Digital systems employing certain logic circuits take advantage of NAND's functional completeness. It shares this property with the NOR gate. This property is called functional completeness. The NAND gate is significant because any boolean function can be implemented by using a combination of NAND gates.
0 Comments
Leave a Reply. |