In this article the basic nanocircuitry is explained in detail. The different parameters like transistors, interconnections and architecture are also explained in detail. The implementing methods and production methods are also explained in detail.
As the term implies, nanocircuits are basic electrical circuits that are designed and operated in the nanometre scale. Even though, the nanocircuit of a processor that is used nowadays will be billion times smaller, the performance will be moreover the same with perhaps greater efficiency. Thus hundreds of nanocircuits can be added together to form a high performance and highly efficient processor. In the case of nanocircuits, it mainly constitutes three basic components. They are
Transistors are used in most electronic circuits as they help in amplifying the weak signals and converting them to strong ones, turn on or off the current through the circuit, and also help in directing the flow of electricity. The transistors used in electronic circuit are made out of silicon as the material an easily switch between the conducting and non-conducting states. When it comes to nanocircuits, the silicon will be replaced by inorganic structures or organic molecules in the nanoscale.
Interconnections refer to the connections between the transistors and other wires in a single device or chip. These interconnections can be done only with the help of logical and mathematical operations. The transistors inside a nanocircuit will be connected together with the help of nanowires which have a thickness of only 1 nanometre. The nanowires are made from carbon nanotubes. But recently, researchers were able to develop nanowires with the integration of transistors in it. Thus the difficulty in stringing the transistors on to the nanowires has been overcome.
The architecture of the nanocircuit is basically the design of the device and has been already discussed in the above topics. As the circuit is very small in nature, they are liable to have more defects. With the help of a good structure combining with redundant logic gates, the whole design can be reconfigured at greater levels of the chip. Thus problems that are liable to happen in the future can be easily repaired.
Many methods are being tried out to implement nanocircuits in the best way possible. Some of the common methods that have been tried out are
- Quantum dot cellular automata
- Single-electron transistors and
- Nanoscale crossbar latches
But, researchers are now more interested in incorporating nanocircuitry with semiconductor devices like MOSFET’s. Since MOSFET’s are used in most of the analog and digital circuit designs, their scaling down will be of great importance in the coming future.
Out of all the FET’s the nanoscale reduction was most successful with the circular cross section vertical channel field effect transistor.
A company called nanosys was able to develop a lateral channel on an FET using nanowires to design the substrates. These nanowires were made using different aligning methods and solution based deposition. Though the total size of such a component was not reduced to that of a single nanowire FET the reliability of the material was much higher. As usual fabrication processes are enough for such a design large volume printing can be easily done at reasonable costs. Such an FET can be made by low temperature deposition and hence can be used as the carrier substrate for transistors. This feature helps in making different electronic devices like electronic paper, bendable flat panel displays and also wide area solar cells.
The basics of nanocircuits and its production mainly depend on the Moore’s Law.
The law is used to relate the number of transistors that can be added to a silicon IC with its computing speed. If more transistors are added, the faster the computing speed.
This is the main reason that nanocircuits are being developed so that more billions of transistors can be integrated onto a single chip to form a super computer. The only problem that will arise with such a sleek design is the defects in the transistor alignment. Nanocircuits will have more problems than larger chips as they are more sensitive to cosmic rays, electromagnetic interference and also temperature variations.
As these transistors will be closely packed, the number of unwanted signals may increase and interference problems may occur. Even the heat produced is difficult to dissipate. Another problem will be the tunneling over the insulation barriers and the fabrication difficulties which will decrease the efficiency of the device.
Due to all these reasons, there will be a delay in the official release of nanocircuits in the market and will mostly be ready by 2016. But, for the production of such devices, the investments should be as high as $250 billion. The principle of Moore’s law is also likely to diminish as there will be a future when the speed of computers will reach a maximum level.