We owe a lot to silicon. Very much, actually. This chemical element has been the king of semiconductors since it dethroned germanium in the 1960s and established itself as the semiconductor with the most potential and the one most used by the electronics industry. In addition, it belongs to the select lineage of the elementary semiconductorswhich are those that are made up of a single chemical element.
Its physicochemical properties have given it the leading role it plays not only in the electronics industry, but also in other very important ones, such as, for example, in the manufacture of photovoltaic panels. Even so, silicon is not perfect. Little by little, and as photolithographic processes have been developed, we have been approaching their physical limit, so it is crucial to find new materials that can take their place.
Scientists have been at it for many years, and they’re flirting with some extraordinarily promising candidates. One of them is gallium arsenide (GaAs), which, as we can guess even if we are not familiar with chemistry, is composed of gallium (Ga) and arsenic (As). But it is not our only option. It may not even be the best. And it is that a scientific team led by researchers from MIT has found a semiconductor that has amazing physicochemical properties.
More efficient and, in theory, more attractive than silicon on all fronts
Before going any further and in order to establish the basis of this article, it is worth briefly reviewing what a semiconductor is. We can define it intuitively as an element or a compound that under certain conditions of pressure, temperature, or when exposed to radiation or an electromagnetic field, behaves like a driverand therefore offers little resistance to the movement of electric charges.
However, when it is in other different conditions, it behaves as an insulator. And, therefore, in this last state it offers great resistance to the displacement of electrical charges. In elements with electrical conduction capacity, some of the electrons in their atoms, known as free electronscan pass from one atom to another when we apply a potential difference at the ends of the conductor.
Precisely, this ability to move electrons is what we know as electric current, and we all know intuitively that metals are good conductors of electricity. Interestingly, they are so because they have many free electrons that can move from one atom to another and thus manage to carry the electric charge.
Electron holes reflect the absence of an electron when it leaves its original atom. They also contribute to the passage of electric current
Another property of semiconductors that is worth briefly exploring, but need not delve into since it is relatively complex, is the mobility of its components. electron holes. They reflect the absence of an electron when it leaves its original atom, and, as we can guess, they also contribute to the passage of electric current in semiconductors.
After doing this little review we are ready to understand without effort why the semiconductor proposed by the scientific team that I mentioned a few paragraphs above in the article published in Science is so promising. Unlike silicon, cubic boron arsenide (c-BAs), which is the real protagonist of this text, is not an elementary semiconductor. And it is not because it is composed of two chemical elements: boron (B) and arsenic (As).
To draw the conclusions they have reached, these researchers have used highly advanced microscopy techniques. One of the most attractive properties of the high purity cubic boron arsenide with which they have worked is, according to their study, its high thermal conductivity. This parameter evaluates the ability with which a material transports heat, and, according to its measurements, in this area this semiconductor multiplies by ten the thermal conductivity of silicon.
Cubic boron arsenide stands out for its high thermal conductivity, and also for the mobility of both free electrons and electron holes.
However, this is not all. They also claim that the mobility of both free electrons and electron holes is unusually high in cubic boron arsenide, which, in theory, opens wide the door that invites us to use this material in the production of much more efficient semiconductors than the current ones. There is no doubt that it sounds very good.
The description published by these scientists in their article argues that cubic boron arsenide is very close to the theoretical concept of ideal semiconductor, so it not only has the potential to mark a very profound turning point in the electronics industry; it could also change the rules of the game, for example, in the field of solar cell production, and even in the electrification process that the automobile industry has embarked on.
The challenge: moving from theory to large-scale production
The authors of this scientific article have it very clear: cubic boron arsenide is the best semiconductor they know. The one with the most attractive physicochemical properties. However, in their study they unambiguously acknowledge that much remains to be done before this material can be used on a large scale. In fact, it may take many years to reach this status. And, even, it is possible that it never achieves it.
The authors of this scientific article are very clear: cubic boron arsenide is the best semiconductor they know
The main challenge that these researchers now face is none other than to take a step forward to find a way to produce it with the necessary purity and in large quantities demanded by industries that can take advantage of it. And the way to achieve this requires further investigation.
Whatever happens, the existence of semiconductors with the ideal properties for replace or coexist with siliconlike gallium arsenide or cubic boron arsenide, invites us to look to the future with very reasonable optimism.
Cover image: TSMC
More information: Science