If you have any interest in electronics then you’ve probably noticed just how rapidly the field advances. Devices that start as bulky and expensive luxuries seem to inevitably find their way into compact form factors that might even fit in our pockets. Computers, for example, used to take up entire rooms while drawing an immense amount of power. Today everyone has far more powerful computers in their phones. And energy requirements are so low that it’s often feasible to power them through small portable solar cells. But have you ever wondered how this level of advancement takes place? How is performance increased, power consumption decreased, and form factors minimized?
Part of this is simply due to miniaturization and advancements in research that allow for bootstrapping. Moore’s Law is one of the most well-known examples. The law, though it’s more of an observation, states that the number of transistors on a chip doubles every two years. As such this means that the capabilities of a device will improve at an exponential rate. On top of that the previously mentioned bootstrapping allows for the implementation of existing concepts in more efficient ways. For example, a processor that doesn’t need to support legacy techniques can remove what’s been proven redundant or superfluous. This allows for smaller and more efficient new architectures at the heart of many smaller electronic devices. However, what makes Moore’s Law and similar observations possible? That’s a deceptively complex question. But the heart of the answer can be found in a single word – semiconductors.
What is a semiconductor? It’d be accurate to say that the name says it all. A semiconductor can conduct electric current in a modulated fashion. It’s not a full conductor like copper. But neither is a semiconductor an insulator like rubber. But at the same time, a semiconductor isn’t just a crude mix of the two extremes as you’d find in standard wiring. Natural semiconductors like silicon are part of what’s made the current level of technological advancement possible. Silicon dominates semiconductor production due to its abundance and versatility, but other materials like gallium arsenide and silicon carbide offer advantages in specific applications. However, the real magic occurs through semiconductor manufacturing.
The composition of raw material with semiconductive properties can be subtly changed on a controlled scale. One of the most basic forms of this manufacturing process is adding tiny impurities. The description might sound like a negative feature, but it’s quite the opposite. A controlled modification with impurities allows the level of conductivity to change according to the manufacturer’s intent. This too is an incredibly complex topic. But it can be understood a little better with metaphor.
Imagine if you could magically change a pipe so that it only allowed liquid to flow in one direction. You’d never have to worry about backflow and even elements of pressure control would be improved. Something similar can be done with semiconductor manufacturing and directional flow. It’s just that in this case, it’s electricity rather than water. This also allows for electrical amplification. Put those elements together and you can see how the modern world of optimized electrics came to be.