Introduction

As the pace of innovation in areas such as EVs, renewable energy and 5G increases at a rate of knots, engineers are increasingly looking for new solutions, pushing technology further to meet consumer and industry demands. I am asking for a lot. SiC semiconductors are one of the answers and are on an exciting path of improvement, already delivering cost-competitive performance compared to older technologies.

Thinking about the price of innovation with SiC semiconductors

Irish poet, novelist and clergyman Oscar Wilde wrote in his play The Fan of Lady Windermere that the cynic is someone who "knows not the price of everything and the value of anything". . It was meant to be a putdown for those with a short-sighted view of the situation without looking at the wider picture. He contrasts the cynic with the "visionary" who focuses on benefits rather than costs.

Power engineers cannot ignore component prices, but there are complex, time-varying, and often difficult-to-quantify cost benefits. Power semiconductors are one example. The innovative and relatively recent disruptive technology of SiC semiconductors was very expensive when first commercialized, and most engineers are unaware of its potential advantages over silicon-based products such as IGBTs and Si-MOSFETs. I was aware of it, but put it far down on my "nice to have" list. However, as SiC semiconductor prices have fallen, performance has improved, and reliability has been demonstrated, it has moved up the list and can be seen as a replacement for existing older technology parts, and a starting point for new designs. . Their adoption is application dependent.

Solar and EV engineers were early adopters where efficiency improvements were a top priority, but the value of lower die costs, better performance, energy savings, and related component cost reductions are considered. With a much wider range of applications'' there is no reason not to switch.

Qorvo's SiC FET devices with normally-off cascodes, such as fast switching, pushed the limits even further. the Company latest addition to the UF series has the lowest on-resistance in its class for 1200V and 650V devices, less than 9mOhm and 7mOhm respectively. These devices have a low-loss body-diode effect, are inherently robust against overvoltages and short circuits, and are as easy to drive as Si-MOSFETs and IGBTs. In fact, the TO-247 package allows many of these components to be drop-in replacements for immediate performance gains. For new designs, Qorvo has also introduced a low-inductance, thermally enhanced DFN8x8 package that takes advantage of the high frequency capabilities in the case of SiC FETs.

System energy efficiency savings are increasingly driving design decisions in favor of SiC-FETs. If the system is designed around SiC-FETs, switching frequencies can be increased without significantly compromising efficiency, and components such as discrete rectifier diodes and snubber networks can also be eliminated.

As a result, the size, weight and cost of other related components such as heatsinks, inductors/transformers and capacitors are reduced. In extreme cases, the entire cooling system with its own inefficiencies can be made redundant to save even more. Especially in EV traction inverter applications, there is a virtuous cycle of increasing efficiency, allowing the components of SiC-based inverters to be smaller and lighter.

SiC semiconductor technology continues to evolve with the promise of future performance improvements. In the next generation, on-resistance will drop further along with switching losses, voltage rating will increase, die will shrink further, yield will increase, and cost will decrease. More variations are coming along with a wider choice of packages suitable for expanding the range of applications at higher voltage and power levels.

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