The current structures for semiconductor central processing units (CPUs) are being designed and produced with some dimensions in the single digit nanometer realm. Beside being hard to make, there are material challenges. When one wants to build a structure, whether it is a large building of a very small line, the roughness (irregularities) in the edges are an issue. Bricks can be off a little with respect to each other and still create the appearance of a straight line. But, if there were large stones on a small wall, the appearance would be very obvious. As the size of the lines and objects get smaller and smaller, the molecules that create the structure can be large enough to irregularities in the structure, which can create issues with the electrical properties of the devices.
Smaller structures would appear to be able to be created faster and with less energy. If the structures need to be more precise in alignment and reduction in irregularities, fast exposures might not be the best approach. There are variations in the energy beams doing the exposure. Everything needs to be uniform. One method is to increase the energy required to form the image of the structure, which means making the imaging material less sensitive. This requires a balance of image structure formation and overall throughput of the equipment, which implies greater energy needed for manufacturing. This raises the possibility of needing new materials and new structures.
Reference 1 is from a business and technology guru, George Gilder. He mentions that Huawei has patented a graphene transistor. (Other companies have patented different ideas and structures.) He states: “Huawei’s breakthrough is deeply impressive. Because graphene is a supreme conductor of both heat and electricity, graphene transistors may operate at 10 times, or more, the speed of silicon devices, using perhaps less than a tenth of the power. . . graphene conducts electrons with minimal resistance and graphene transistors need far less power than silicon to switch on and off. But they will be slow no longer, switching at least an order of magnitude faster than silicon. And as a “two dimensional” (i.e., one atom thick) material graphene circuits could function with only atomic distances between them.”
There is continuing development in the area of metamaterials. Engineers from CalTech and ETH Zurich created a method to design metamaterials using quantum mechanics principles. [Ref. 2] Work has been done on bending electromagnetic waves. An earlier set of blogs have described the impact of metamaterials designed for specific purposes. This team approached the design of metamaterials based on quantum theory. The researchers realized that “quantum mechanics predicts the existence of certain exotic types of matter: among them, a ‘topological insulator’ that conducts electricity across its surface while acting as an insulator in its interior. They realized that they could build macro-scale versions of these exotic systems that could conduct and insulate against vibrations instead of electricity by using principles of quantum mechanics.”
Given that it is possible to create metamaterials , how does this relate to semiconductors. As mentioned, creating means of focusing and bending light, open the possibility of creating optical connections in the semiconductor device. Optical waves can move faster than the electrons. This creates increased speed and a lower energy level, which means less energy loss , which would have become heat. So, it would be faster and use less power. What about the transistor itself? With the ability to create metamaterials that function in very different ways, the design tools are coming that could provide the ability to design a new functioning “transistor”. It still needs to be invented. Coming soon?
References:
2. https://www.sciencedaily.com/releases/2018/01/180118100819.htm
