Kevin Parmenter, Field Applications Engineering – North America, Advanced Energy
It’s forward thinking and necessary to have the terms “wide-bandgap semiconductors” and “packaging” in the same sentence. Several years ago, I was involved in the emerging stages of wide-bandgap semiconductor devices. In a meeting, I mentioned that device success in the marketplace required a focus on building a supporting ecology and innovation in packaging technology. This, of course, did not fit the belief that we could put next century technology in 1980’s packages without optimized drivers or controller schemes and expect quick success and returns in a single quarter.
Fast forward to where we are today, and what was needed is now occurring. The GaN and Silicon Carbide suppliers are innovating from the pins in providing incredible technologies that inch us closer to the ideal switch. Frequencies and performance can be increased to unheard of levels. The parasitic capacitances inherent in all semiconductor switches are drastically lowered, making devices easier to drive. Early manufacturing issues have largely been solved – reliability promises to meet if not exceed, that of silicon semiconductor devices, and every day, semiconductor devices are made better and better - including competing silicon devices. The rate of improvement is just getting started, so watch for phenomenal innovations.
In addition to lower capacitances, GaN has no parasitic BJT and no body diode with zero reverse recovery. Increasing switching frequencies, better efficiency, lower losses, fewer parts – smaller filters, smaller heat sinks and enabling new topologies can translate into smaller, faster, and lower total system cost. Silicon Carbide devices enable much of the same; however, higher voltages are routinely possible vs. silicon IGBT’s and MOSFETS. It seems obvious that e-mode GaN devices are going to eclipse cascode devices based on customer preference and what’s being used in new designs. Essentially, if you don’t have e-mode, you better get it before it’s too late.
From the pins out, packaging innovation and progress has been astounding – we see that power electronics design is now like RF power design so that the interconnections and PC Board become part of the circuit. We are now at chipscale levels, eliminating wire bonds and increasing performance and reliability with better EMI performance, improving thermal performance. It’s clear this innovation was needed for the potential of wide-bandgap semiconductors to be realized.
Regarding packaging, we’re seeing the enviable of the needed drivers with impedance matching to the unique capabilities of wide bandgap devices, as well as the programmable digital control ICs needed to take advantage of switches. We’ll see more co-packaging of these into modules with 3D packaging used, building out the ecology. We’re also seeing the reference designs from semiconductor companies as required to accelerate the designs.
These are exciting times in the wide-bandgap and power electronics industry for those embracing the challenges and can face the realities of the market needs by adapting, innovating and delivering on promises. It might even take some collaboration and investment in magnetics design.