It might seem odd to discuss reliability in a blog that focuses on nanotechnology and its implementation. However, if one considers that we are using carbon nanotubes (CNTs) in many different products to increase strength and reduce weight along with the semiconductor circuitry that has nano-scale components, then it might not be too unusual to consider reliability.
Over the last twenty years, there has been a lot of controversy about CNTs. The shape of the CNTs is like a short, straight stick, albeit at the nano dimensions. The appearance of the CNTs resembles five of the six types of asbestos particles. Consequently, this similarity raised concern and a number of studies were undertaken. Results came out on both sides of the issue. Some results showed potential danger and other results indicated with precautions, the CNTs are safe. (We have covered Nano-Safety a few times, so we will not add more here.)
Composite materials employing CNTs for strengthening work well and when the composite is damaged, the release of any of the CNTs appears to be minimal. Overall, the application of the CNTs provides significant benefit for long term usage of items containing the CNT embedded composite. The usage of CNTs in products has only been a few decades. This is not long enough to evaluate the long term effects.
Many attempts have been made to develop carbon-based materials for electronics. Graphene has been covered in detail within this blog. The application of both nanotube and various two-dimensional electronic materials appears to have had moderate success. The question is how to mass produce items/devices in the billions as are being done with semiconductors. This is a challenge.
Semiconductors are coming into the nano-scale regime even if it is not through new electronic circuit components. The line width of circuit features is well below 50nm. The experimental efforts today are at 5nm and below. The circuit designers, material scientists, and semiconductor fabricators are aware of the potential current changes due to leakage of electrons through materials that are barriers to this movement at larger dimensions. New materials are being developed and evaluated. Circuitry mis-performance is always a concern.
The challenges of electronic circuits are what happens when the device ages. Historically, although semiconductors are relatively new, the consumer applications that employ the sophisticated electronics were limited to a narrow range of temperatures. These devices are increasingly being employed in automotive, industrial, and medical applications. Consequently, reliability has become much more important. The aging of devices is becoming a more critical element of the design structure.
The car or truck that we own has become among the most electronically controlled device that we have. The temperature extremes that a vehicle can be subjected to, especially under the hood, can range from -40 F or lower to well above 150 F. An example given is that an automobile that is purchased and driven in Arizona, for example, is subject to significantly different conditions from an automobile that is used in Alaska. There is also a difference in the usage of the electronics. And automobile that is used for work or pleasure will have a limited number of trips during the course of the day or week. A vehicle like a taxi or delivery truck will be under constant usage and subjected to a lot more stress. [Ref. 1] these become part of the new challenges for devices as he electronics becomes more integral into everyday life. The medical field also has similar issues regarding reliability of equipment that is used for performing medical exams or procedures. When a life-sustaining device is employed, the reliability of the operation of that device is critical. Failure is not an option.
The point of this particular blog is to raise awareness of the fact that the reliability of electronics needs to increase. There is work that is being done that will improve the situation. But, what do we do to build a device which can last and perform its intended function for 100 years, or 1,000 years!