By Vandana Sharma
The 21st century can easily be called the era of portable devices that are lighter, smaller and a whole lot powerful in configuration than their predecessors. All this has been possible with the size of the processor shrinking to the nanometre scale. These small sized processors, also called microprocessors, have enabled the electronics manufacturers to build products that are smaller in size, have faster processing speeds and are powerful. However, experts view this development more as the continuation of existing microelectronics rather than a breakthrough in the nanotechnology space. They believe that this is merely a small application of nanotechnology and doesn’t represent even an iota of the potential that nanotechnology holds for the future of electronics.
Indeed, nanotechnology or nanotech, is not merely about reducing the size of processors to nanometres. Its domain is vast and still remains largely unexplored. Considering the research happening across the globe, and the advances so far in this space in terms of the development of new circuit materials and so forth, the technology surely holds a lot of promise for the technologists and electronics industry alike.
Is ‘nano’ the way to go?
With the current materials and technologies nearing the upper limit, scientists and researchers have built a lot of hope around nanotechnology, which according to them can help in developing alternative methods and materials. They believe that someday nanotechnology will revolutionise the global economy by providing power tools that will produce high tech products using low tech resources at low costs.
There is no denying the fact that on the concept level, nanotechnology holds a lot of promise. But in spite of breakthroughs prophesied in this field by many a scientist and futurist, especially if we consider the application of nanotechnology in the field of electronics, there hasn’t been much headway ever since the technology’s emergence in 1990s.
How much does ‘nano’ measure up in size?
Nanotechnology is the study of manipulating matter on an atomic and molecular scale. Generally, nanotechnology deals with structures sized between 1 to 100 nm in at least one dimension. It involves developing materials or devices possessing at least one dimension within that size. However, when it comes to the size, the opinions in the technology space are divided. There are some who claim that 45, 32 or 22 nm technology does not qualify as nanoelectronics.
Vassilios Gerousis, senior architect, Cadence Design Systems, shares, “One opinion, which comes from the research fraternity deals with nodes that are between the dimensions of 10 nm and below, such as carbon tubes. Another opinion coming from the applied research domain caters to nodes between 14nm and 20nm. The third viewpoint is from the application side and is focused on 40nm and 28nm.”
Yet another view is that CMOS technology, does not fully qualify as nanotechnology because it uses mostly top-down fabrication to reach nanoscale
dimensions. “However, the CMOS people themselves consider all technology nodes below 100 nm as nanoelectronics, since they comply with the basic definition of nanotechnology objects, that is, structures with critical features below 100 nm,” says Marc Van Rossum, strategic adviser, Imec.
“Nanoscale is commonly defined as smaller than 100 nm and, by that definition, modern electronics have been at nanoscale for about a decade. This is the definition that Intel uses,” quips Michael Mayberry, director—components research, technology and manufacturing group, Intel.
Clearing the air on the subject, Dr Denis Koltsov, consultant in Nanotechnology, BREC Solutions (UK), says, “The subgroups like nanoelectronics seem to deviate from an official ISO definition of nanotechnology if they are claiming that 45-22 nm technology is still not nanoelectronics. Any device that is smaller than 100 nm in at least one dimension would be classed as nanodevice.”
Dr James Canton, futurist, adviser, CEO, Institute for Global Futures www.FutureGuru.com, adds, “People think that nanoscience is about size, while it is more about capturing in small platform a dense amount of functionality and performance.”
Is nano going mainstream?
If we look at the application side, it is believed that most of the nanoelectronics technologies (at the transistor level) demonstrated today—such as hybrid molecular/semiconductor electronics, one dimensional nanotubes/ nanowires and advanced molecular electronics—are futuristic and not usable anytime in the near future. The industry has had its share of doubts about the wide scale adoption of nanotechnology in electronics. “Currently, in the mainstream we see
40 nm and 28 nm technologies,” says Gerousis. Most of the work that is underway below the 20 nm dimension is in the research and development phase.
The key challenge that is being faced by the industry and researchers is that while the nanomaterials are exotic, these are not easy to produce. Some of the exotic nanomaterials, including carbon nanotubes, have very interesting properties as materials. But the industry still lacks the ability to precisely form and use them for electronics where we typically need to fabricate billions of transistors at once, opines Mayberry.
“The largest of the exotic material demonstrations have been of the order of a handful of devices working together. Nevertheless, considering the pace of science and technology advances, I think eight to ten years from now we might be using some of these exotic materials in electronics production. For applications requiring less precision some of these nanomaterials are already in use,” he adds.
Devices using carbon nanotubes or nanowire transistors show promise for specialised sensors, and there is also some perspective for nanowire solar cells. But molecular devices have only proven their relevance at the diode level, and a genuine single molecule transistor (three-terminal device) with acceptable characteristics is still out of reach.
So, where does the paradox lie? Why a technology that is so promising at the concept level has failed to scaleup when it comes to its mainstream application in the electronics domain? Enumerating a few reasons, Kolstov says, “The research in molecular nanoelectronics is unfortunately very sensational. A research group may measure some effect from one device and write a paper. However, this result has limited use for industrial community since it may not be reproducible, and in some cases is simply wrong. Some recent publications argued that some applications of nanoelectronics may never be manufacturable.”
While it is true that the progress made so far in this domain has still not been too fruitful, yet there are areas where the application of nanoscience has led to interesting results. IBM has done extensive work in nano computer chip development that will likely to extend silicon’s life as a chip platform. Mercedes uses nano on coatings for autos to protect the driver.
Looking beyond processors
The relevance of nanotechnology and nano materials for reducing the size of transistors cannot be ignored. It would be worthwhile to explore a few other areas in the electronics space where nanotechnology can potentially have its influence.
Digital displays: The quality of digital display screens in electronic devices can be improved by reducing the power consumption while decreasing the weight and thickness of the screens. Nano research projects are underway to make use of electrodes made from nanowires to enable flat panel displays, which are likely to be a lot more thinner than the current flat panel displays. MIT researchers have also created a quantum dot organic light emitting diode (QD-OLED). While the traditional LCDs are lit from behind, the quantum dots have the capability of generating their own light, and these dots can be manipulated to emit any colour imaginable, with no range limit as seen with traditional devices.
For larger memory sizes: With consumers demanding electronic devices such as music players, mobile phones and computers with gigabytes of memory, the future electronics devices will surely need even larger memory sizes. “Nanosized magnetic rings are being tried to make magnetoresistive random access memory (MRAM), which research has indicated may allow memory density of 62 GB per sq cm (400 GB per sq inch). Rossum says, “There are many ideas of using nano features in non-volatile memories—molecular structures, metallic nanodots, organic molecules, nanostructured materials and so on. Although their applications are not yet mature, it is still an interesting avenue of research.”
Making existing technologies better: “This new technology is not only about doing things better, faster at a smaller scale, but also about adding new functionality to existing technologies,” says Kolstov. “The devices, sensors, etc, are gaining another option, like, for example, the development of Spin-FET. In that case the charge and spin of the electrons are used to offer novel functionality,” he adds.
For healthcare and environment: “In the future nano will be about designing matter at the atomic level to address climate change, hunger, war, healthcare and energy needs,” believes Dr Canton. In the future, convergence of nanoelectronics with bioelectronics could be important for health and comfort applications, provided the technology becomes affordable. “Already, nano wires are being used to restore movement in crippled legs, by restoring neural pathways to connect the brain to the body for movement,” informs Dr Canton.
Faster data transfer: Optoelectronics can help in dramatically increasing data transfer rates within devices like PCs by replacing the existing copper wiring. Instead, in the future, quantum dot based lasers may also be used to transfer information between components within devices at the speed of light, with each piece of information ‘coded’ using a unique wavelength of light. If we look at external networks, data transfer can take place more rapidly between two points if we increase the number of nodes in information networks. This will become possible through the development of cheap ambient sensor networks based on nanotechnology, and will help the telecommunication sector to achieve better data transfer rates.