What is Nanoelectronic?
Nanoelectronic is concerned with understanding and exploiting the properties of devices, which have dimensions at the nanometre scale.
Microelectronics will gradually evolve into nano-electronic. In fact, this has already happened as can be seen from the smallest feature size of present integrated circuits, which is below of one micrometer. It is currently believed that optical lithography can be used for ground rules down to 150 nm and might even be used for the 100 nm generation and below. This would imply an increasing process and mask complexity, and consequently, increasing the cost.
Molecular-scale electronic has been widely touted as “the next step” in electronic miniaturization, with theory and research suggesting that single molecules may have the capability to take the place of today’s much larger electronic components.
Therefore, what are the advantages of scaling down of devices?
Speed of operation – Reduction of the parasitic capacitances associated with non-conductive paths in an electronic device leads to a higher cut-off frequency. This enables a device to operate at much higher speeds. Density – An obvious advantage. This reduces size and cuts materials cost. Power dissipation – This is reduced due to lesser resistance in interconnects and currents flowing in smaller circuits. In lasers, the use of lower dimensional systems reduces the threshold current due to improved density of states distribution. New applications – This enables certain uses, currently speculative, but very much in the offing.
Integrated circuits are also known as microelectronic. The term micro derives from micro-fabrication technology, which embraces all highly sophisticated techniques like optical- and electron-beam lithography, metallization, implantation and etching that allow generating structures on the scale of one micrometer.
In the early 1970’s, two scientists, Ari Aviram and Mark Ratner, began to envision electronic circuit elements made from single molecules and described in detail how they might function. This was the origin of the field of molecular electronics, now sometimes called molecular-scale electronics.
The emergence of molecular electronics and spintronics is providing a challenge to traditional electronic manufacturing techniques. Significant reduction in size and the sheer enormity of numbers in manufacturing are the benefits of molecular electronics. Scientists predict that computers will be assembled using molecules in the future, pushing technology far beyond the limits of silicon.
Satish P. Nair, Technical Insight Analyst says “The future of electronics is nano-sized, exciting nanofabrication techniques have unfolded different methods to engineer nanowires, quantum wells, and nanotubes which function as the building blocks of future nanoelectronic devices.” The progress in carbon nanotube and semiconductor nanowire has provided researchers with a model against which to gauge future nanoscale devices and systems.
Adds Nair: “Molecular electronic can create devices that could be a thousand times smaller than current semiconductor-based devices. Molecular memories will also have a storage density million times that of today’s best semiconductor chips.”
Dramatic breakthroughs in molecular electronic by industry giant Hewlett Packard (HP) and other major developers validate these predictions. HP has created a new kind of minute circuit for computer chips using nanotechnology. The company’s research laboratory also announced the development of the highest density electronically addressable memory to date.
Nair notes: “Research indicates that the time-to-market for commercial applications of Nanoelectronic-based devices is shrinking with the years. It is predicted that within the next five years, we will probably witness the first complete based-based device in the market.”
Nanoelectronic areas being studied include the fabrication of atomic wires; Single Electron Tunnelling (SET) devices and atto-farad structures; and the study of spin-polarised electronics and magnetic nano-structures, all of which are likely to play an important part in future electronic devices. A study of the thermal motion of an isolated surface-trapped atom will also be carried out and its potential as a nano-scale noise thermometer investigated.
By growing nanowires that are 20 to 200 nanometers in diameter (one nanometer is one one-thousandth of a micrometer and human hair is typically 50 to 100 micrometers thick), researchers say they are closer to creating the circuitry required for nanoelectronic devices.
Research and development in nanoelectronic has been fuelled by huge investments by various national governments, as it is happing with nanotechnology in general. Countries in Europe and Asia, notably Japan and China are expecting to spend – and reportedly spending at the present – millions of dollars in the field of nanoelectronic.
