Introduction to Nanoelectronics
New technologies need new materials with higher physical, chemical and mechanical properties. When the grain size is usually reduced to below 10 nm, most electronic and optical properties differ. Their mechanical, chemical and many physical properties, however, start to differ substantially from bulk below 50-100 nm. Nanomaterials can be defined as those materials that have at least one of their nanometric range dimensions, below which the property of interest varies greatly compared to microcrystalline materials.
Impacts of nanotechnology
Smaller size means operations for a given output at higher frequencies, greater functionality, lower manufacturing and lower power. Memory space and data rates for transmission will increase. Health diagnostic equipment is faster, more practical, and more precise.(Lab-on-chip). In pharmaceutical products, nano-particles enhance their absorption inside the body and make them easier to administer, often through a combination of medical devices.
By constructing vehicle parts that are lighter, stronger and more chemically resistant than metal from nanocomposite materials, vehicle fuel efficiency and corrosion resistance can be improved. Without a substantial increase in weight, thickness or rigidity of the fabric, nanoparticles or nanofibers in fabrics can improve stain resistance, water resistance, and flame resistance.
Limitation of microelectronics
It seems fair that Moore's law would have to slow down the pace of scaling down.
Several factors are linked to technical limits:
The amount of heat produced by the energy consumed and which cannot be extracted due to the material's thermal conductivity limits and the growing number of overlayers. As the size of the area to be doped is reduced to about 0.1μm3, the number of doping atoms becomes so low (about 10) that it is not possible to properly monitor the "parameter spread" in fabrication.
Physical Boundaries:
Thermal limit: The energy required for a bit of writing should be many times kT, which is the average thermal fluctuation energy.
Relativistic limit: it is unlikely for signals to spread faster than the speed of light
Principle of uncertainty: According to the Heisenberg principle of uncertainty, the energy & time required to write or read a bit should be related to ΔE.Δt ≥ h
Developments In Nanoelectronics & Optoelectronics
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| Evolution of the minimum feature size of a Si DRAM |
Today, it is assumed that current Si technology will continue to develop one order of magnitude lower towards feature sizes, i.e. L ~10 nm; But below this scale, it will be appropriate to build transistors based on new concepts such as single electron transistors, resonant tunnelling devices, etc.
The principles of mesoscopic & quantum physics must explain the function of this new form of system. Due to developments in the deposition of very thin films to form heterostructures in which electrons could be limited to a 2D mesoscopic device, evolution towards nanoelectronics was possible. We are presently close to the limits of traditional optical lithography and other nanolithographic techniques of high resolution.
Superconducting electronics: consists of 2 superconducting layers separated by a very thin isolating film of oxide, which can be tunnelled by superconducting electron pairs. High switching rates, sum of dissipated power is very low and the resistance of interconnect superconducting lines is virtually null.
Spintronics-which exploits electron spin orientation. By enclosing a semiconductor layer (base) sandwiched between two ferromagnetic layers (emitter & collector), electron-spin transistors are constructed. Electrons gaining the emitter's magnetization state will only pass through the collector through the base if their spins are compatible with the collector's magnetization.
Molecular electronics: This is based on the various states or configurations that molecules can take, such as "trans" or "cis" as well as the unpaired electron spin parallel or antiparallel alignment.
Bioelectronics:trying to replicate nature - for nanotechnology norms, a neuron is very large. The parallel processing capabilities as well as their 3D architectures and the topology of the interconnects are what nanoelectronics try to mimic biological neurons
Optoelectronic Integrated Circuits (OEIC): laser diodes are generated in chips using standard integrated circuit technology, combined with transistors and optical interconnects.