4月 11, 2017
Gallium nitride (GaN) is a better semiconductor than silicon. There are many crystals that are better than silicon, but the problem has always been that they are far too expensive to be used in every application where silicon is used. But, GaN can be grown as an inexpensive thin layer on top of a standard silicon wafer enabling devices that are faster, smaller, more efficient, and less costly than their aging silicon counterparts.
This breakthrough for growing GaN on silicon can be viewed as a means for the extension of Moore’s Law, a “law” that has run out of steam in the past few years due to the performance limitations of silicon. However, just classifying it as an extension of Moore’s Law is proving to be too narrow a view of the impact of GaN technology on the way we live. In fact, GaN is proving to play a key role in a radical shift in how we allocate our planet’s precious, and dwindling, resources. Let’s look at four ways GaN -- in end-use applications -- is helping us be kinder and gentler on our planet.
Autonomous vehicles and the transportation revolution
LiDAR (Light Detection and Ranging) as a way to measure the distance between two objects has been around for over 50 years. The way this technology works is that the LiDAR system flashes a beam of light and measures the time it takes for that beam to bounce off a distant object and return to the detector sitting next to the original light source.
LiDAR has become a core technology behind autonomous vehicles because it can provide a fast (virtually instantaneous) and extremely accurate 3D image (or three-dimensional point cloud) of the surrounding environment (see figure 1). The reason LiDAR can paint such a fast and accurate image is that the lasers are “fired” by GaN transistors and integrated circuits. The speed and accuracy at which GaN can fire the laser is fast enough to create high-resolution images needed for the fastest autonomous racecars.
Figure 1. GaN provides faster and more accurate LiDAR images than silicon
Autonomous vehicles will become a reality, although the exact timeline is still uncertain. When this happens, imagine the impact it will have on our entire transportation system and the urban landscape. Individual car ownership will be a thing of the past, since we will be able to order a driverless car for the number of passengers and the range needed at that moment. Parking lots will disappear, road congestion will be reduced, and, most significantly, traffic deaths will be eliminated.
In addition, the cost to the consumer for vehicle transportation will be significantly lower as less capital will need to be invested in a vehicle, and fewer taxes will have to be paid for transportation infrastructure. We can assume that the majority of these autonomous vehicles will be electric, thus further reducing the stress on energy consumption, air quality and greenhouse gas emission.
Drone package delivery and the logistics revolution
Another type of autonomous vehicle that will reduce stress on our environment is the drone. As with autonomous vehicles, GaN-based LiDAR is key to autonomy with drones, but drones have a different challenge; they have limited range when powered by batteries. Imagine the amount of traffic that would be reduced if all our small packages were to be delivered by drones. This is not a dream – it is now possible, thanks to the ability to charge drones in mid-air using wireless power transfer.
Shown in figure 2 is a drone being charged from a small antenna driven by GaN transistors. These low-cost and light weight charging platforms could be mounted on every street light, thus enabling drones to recharge as needed while on their package delivery missions. These antennae can also be fitted with a battery pack and a solar panel. In this configuration they can create long-distance trails of autonomous charging stations that could give access to the most remote and dangerous locations on our planet for critical deliveries of food or medical supplies.
Figure 2. Drone being charged from a small antenna driven by GaN transistors
Eliminating power cords
Wireless recharging of drones is just one example of our ability to transfer energy without wires thanks to the speed and efficiency of GaN. On a broader scale, we are on the verge of eliminating power cords in the home using a technology called resonant magnetic energy transfer. This technology was invented at MIT earlier this century and serves as the means for “cutting the cord” and freeing the home and work environment from messy power cords.
In figure 3 is a desktop that has been built with a low cost antenna just under the top surface. Using GaN integrated circuits to achieve efficiencies similar to devices with power cords, this desktop is able to directly power an array of diverse electronic devices positioned anywhere on the surface.
Figure 3. Desktop built with low cost antenna under the top surface to wirelessly power devices placed on it
Imagine this type of powered tabletop in your kitchen, or in the conference room at work, or in your living room powering your sound system and TV without wires. A world without power cords would be more efficient – TVs, radios and illuminated artwork could be hung anywhere on the wall without the need for wall sockets and unsightly power cords. In addition, not having to “plug in” would eliminate countless electrical fires that destroy many homes and lives each year.
Making artificial intelligence and deep learning less harmful to our environment
We are experiencing a fast escalation of the demand for massive server installations to support big data, cloud computing, deep learning, and artificial intelligence. According to Fujitsu, data center energy consumption accounts for up to 2% of all electricity use worldwide. Even though there is no way the demand for computing ability can be reversed, computing can be made less costly to our environment by reducing the need for energy, and here is another major contribution of GaN technology.
Figure 4. GaN reduces the energy needed to run data centers, which are expanding rapidly due to the increasing demand for computing power
Due to GaN’s high efficiency, we can contribute to the Open Compute energy consumption goal by saving between 10 and 20% of the energy used by data center server farms. Additionally, significant energy savings can be harvested from the reduced need for cooling of these massive server installations. Now, all we have to worry about is whether the computers will be smarter than humans!
GaN technology is enabling many new applications that were just not possible with silicon semiconductors. Given above are just a few examples of how GaN technology is changing the way we live. Efficient Power Conversion (EPC) was founded based on the goal of replacing silicon semiconductors with a technology that is far more efficient and lower cost to produce. As it turns out, GaN is doing so much more than just saving money by replacing aging silicon components, GaN is enabling new applications that significantly reduce the resources we need to drain from our planet while making our lives safer, healthier, and more fun.