markets wide bandgap electronics
associated with the manufacture of SiC substrates. Its rival, GaN, is now arguably the best semiconductor material, in terms of the combination of performance and cost. It is used today for making RF power amplifiers, thanks to its inherent advantages in voltage and temperature performance over GaAs. Strengths of this wide bandgap semiconductor include the promise of making devices with incredibly low loss, and the opportunity to deposit epilayers on standard silicon substrates. The latter virtue enables production costs to be significantly below those for SiC.
At IMS Research, a market research firm based in the UK, we have been looking at various applications for SiC and GaN power semiconductors, and figuring out how they will evolve over the next ten years. In the remainder of this article we’ll look at the impact of this pair of wide bandgap devices on a wide range of applications: Power factor correction (PFC) power supplies, uninterruptable power supplies (UPS), hybrid and electric vehicles, industrial motor drives, PV inverters, wind turbines, and traction.
For SiC and GaN devices, many of the barriers to mass adoption are similar. Neither of these devices will make a big impact until their prices approach those of silicon SuperJunction MOSFETs and high-voltage IGBTs. This affordability target will be pursued through moves to manufacture on larger substrates and improve material quality.
Other factors that will determine how quickly SiC and GaN devices can make an impact are: The time taken for SiC and GaN transistors and power modules to demonstrate long-term reliability in long-life industrial or health-and-safety-critical applications; how quickly the strength of competition increases between the qualified suppliers of SiC wafers and GaN-on-silicon epitaxial wafers; and whether there will be new legislation or government initiatives on the energy efficiency of power electronic systems. Greater competition from increasing numbers of established power semiconductor manufacturers offering SiC and/or GaN products will also help to drive greater adoption of wide bandgap devices, which can sell in higher volumes as their portfolios broaden. The SiC product range should grow to include higher-voltage devices operating at 1700 V, 2.5 kV, 3.3 kV, 4.5 kV and above, plus GaN diodes and transistors at 1200 V and above.
Power supplies
PFC power supplies were the first key application to use both forms of wide bandgap power device. In this sector, the long-term winner is likely to be GaN. 600 V and 650 V will be the typical device voltage ratings for power supplies in consumer and office equipment running off of the mains, and we forecast that GaN transistors and diodes operating in this regime will cost less than SiC-based equivalents – they could ultimately match silicon prices. Industrial three-phase mains power supplies sell in smaller quantities than PFC supplies, and they require 1200 V-rated devices, a requirement that is easier to satisfy with SiC technology. SiC and GaN switches offer substantial benefits in PFC
July 2012
www.compoundsemiconductor.net 31
stages of hard-switching power supply units (PSUs); less so in soft-switching circuits. The increase in power conversion efficiency is actually quite small – perhaps tenths-of-a-percent to 1 percent. The far bigger gain resulting from the introduction of wide bandgap electronics in a substantial cut in the size of the PSU, with increased power density made possible by fewer, smaller secondary components required in the snubber circuit. The reason behind this is the opportunity to increase switching frequency, which is made possible with SiC and GaN diodes.
Few vendors of the other big selling class of power supplies, the UPS, are building products incorporating SiC or GaN power devices. However, the relatively small market for SiC Schottky diodes in UPS is no reflection of the improvement wrought with wide bandgap semiconductors. In our view, in UPS, the revenue potential for SiC or GaN Schottky diodes is relatively small. Sales should be greater for SiC power transistors and SiC hybrid and full-power modules. We predict that discrete SiC and GaN power devices will be used in just smaller single-phase UPS systems rated up to 5.1 kVA, while SiC power modules will be deployed in UPS systems rated between 5.1 kVA to 250 kVA.
Better electronics for better cars Exciting opportunities for wide bandgap power devices also exist in the hybrid and electric vehicle market. Adoption of the devices could increase inverter efficiency, leading to a longer vehicle range between recharges.
There are three potential areas for the deployment of wide bandgap devices in hybrid and electric vehicles: The mains battery charger, found only on plug-in hybrids and battery electric vehicles; DC-DC voltage conversion systems; and the drivetrain. Increasing the power density in these electronic systems, which is possible with a switch from silicon to wide bandgap semiconductors, allows for reductions in size and weight. This is highly desirable because space in an electric car is tight, and using less of it for electronic systems gives designers more freedom. In addition, reducing weight increases the vehicle’s acceleration and range.
Inverters are needed to convert the DC output from the cells into an AC form that can be fed into the
grid.Increases in efficiency that lead to better returns are possible by replacing the silicon electronics in the inverter with SiC devices
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150 |
Page 151 |
Page 152 |
Page 153 |
Page 154 |
Page 155 |
Page 156 |
Page 157 |
Page 158 |
Page 159 |
Page 160 |
Page 161 |
Page 162 |
Page 163 |
Page 164 |
Page 165 |
Page 166 |
Page 167 |
Page 168 |
Page 169 |
Page 170 |
Page 171 |
Page 172 |
Page 173 |
Page 174 |
Page 175 |
Page 176 |
Page 177 |
Page 178 |
Page 179 |
Page 180 |
Page 181 |
Page 182 |
Page 183 |
Page 184 |
Page 185 |
Page 186