Alternative Energy Markets Create Opportunities for Power Management Semiconductor Technology
Demand for energy efficiency is creating a new growth market in power semiconductor manufacturing. Healthy demand continues for improved designs for low-voltage power management devices to reduce the energy consumption of all sorts of mobile and consumer electronics products. At the same time, alternative energy markets are starting to generate significant volumes for advanced high-voltage power semiconductor manufacturing technology, for vehicle electrification, solar and wind generation, and electrical grid upgrades.
Better power electronics alone have the potential to reduce the world’s electricity consumption by some 20-30 percent by 2025, by more efficient electronic control of more of the world’s growing numbers of motors, lights and IT systems, argued several speakers at the recent Applied Power Electronics Conference.
These new markets will help spur a period of new sustained double-digit growth for the old power management semiconductor sector. Total sales will increase some 14 percent to $36.2 billion this year, and continue on a 15 percent CAGR trajectory to add some $13 billion in new revenues to become a $45 billion market by 2014, according to IHS iSuppli. Analyst Marijana Vukicevic projects better than 20 percent annual growth for MOSFETs that handle large amounts of power, a doubling of sales of DC-AC inverters to a $7.2 billion market, and a $25.3 billion total market for smart power management ICs by 2014.
Demand for PV inverters is expanding with the solar market, on track to surpass $4 billion in sales by 2015, reports Yole Développement. The smart grid is a growing market as well, driven particularly by a major push to install smart meters in China. That’s driving 29 percent CAGR in units, to generate a $5 billion market for the meters by 2015. Smart systems for more efficient distribution of electricity on the grid will also require new high-end power management semiconductor technology, although utilities aren’t going to really start investing in these technologies in volume until after 2015.
Though the hybrid and electric vehicle market remains small, and dominated by Japanese auto makers with internal supply chains, all the other major automakers around the world are now developing hybrid vehicles, and most are at least looking seriously at hybrid plug in and all electric vehicles, opening the market to new suppliers and new technologies, notes Jon Cropley, IMS research director for the automotive & transport research group. Mainstream autos are going more electric as well, points out Cherif Assad, business leader for global power train and hybrid electric vehicles at Freescale Semiconductor. He says that government mandated fuel efficiency and emissions requirements (especially in Europe) can only be met by electronically controlled smart power management, from systems that automatically turn the engine off and on instantly as the car stops and starts in city traffic, to electric motors that replace mechanical oil and water pumps.
Looking to New Substrate Technology to Improve Efficiency, Size, Cost
Power device makers see improvements in substrate technology as key to many of these new markets, from superjunction and neutron transmutation doped silicon, to SiC, and GaN. The latest power semiconductor technology roadmap from the Power Sources Manufacturers Association reports growing interest among users in GaN devices due to stated performance advantages in specific-on resistance, breakdown voltage, switching frequency, system efficiency and power density. Roadmap co-chair Aung Thet Tu, Power Conversion America product line director for Fairchild Semiconductor, reported silicon MOSFETs, and in particular, super-junction devices continue to gain market share. SiC diodes are now prevalent in AC-DC front-end power supplies and SiC has even found its way into advanced thermal management materials as silicon-carbide particle-reinforced aluminum (Al/SiC). IMS has noted that 57 percent of OEMs surveyed said they are using or planned to use SiC in their designs.
TranSiC and SemiSouth both say they’re selling all the SiC devices they can make, both the new BJT and JFET switches and more established SiC diodes, driven by demand for improved efficiency for power management for solar systems. Cree’s new SiC power MOSFET also targets high-voltage power supplies and power conditioning now, then motor drive control, electric vehicles and wind power applications in the future. The company was demonstrating a high-voltage 10kW power supply— reduced to about the size of a shoebox— at the APEC show, that reportedly would replace a current table-sized unit. The new SiC MOSFET is so far going mostly to developers to figure out what they can do with this new capability for drastically reduced size and materials use. Cree expects costs to come down with volume production, noting the company’s recent >40 percent per year decrease in cost per lumen of its LEDs, in part from scaling the volume of its SiC wafer production.
GaN-based power conversion devices are poised for commercialization, argued Tim McDonald, VP of emerging technologies at International Rectifier. “There will still be improvements from next generation silicon, but we’re reaching the point of diminishing returns,” he said, “So GaN is next.” The company sees the potential for GaN-based power conversion products offering 2-3x better performance/cost than existing silicon solutions. This is enabled by achieving 10x performance FOM improvement while realizing cost for the substrate plus epi that’s less than $3/cm2 McDonald projected that 1-2 percent of all power conversion applications will use GaN in 3-5 years. Currently the company is reportedly growing 4µm epi layers without cracks and with low current leakage. IR released its first GaN based device in 2010 and the company’s GaNpowIR manufacturing platform is capable of <50µm bow for GaN on Si wafers, and has demonstrated >10 million device hours reliability. Low voltage performance hits 88 percent efficiency at 5MHz (Vin =12V, Vout= 1.8V). IR plans to introduce 600V GaN on Si devices later this year. Though GaN potentially offers higher temperature performance, the initial devices are currently rated at the same temperatures as silicon. “It’s a packaging issue,” says McDonald. “The package has to catch up.”
“There’s also still a big opportunity for improving silicon,” says Yole Développement analyst Brice Le Gouic, noting products like STMicroelectronics’ 1200V superjunction silicon MOSFET. Here companies are at work to get better performance at lower cost from improving multiple epi-layer or deep trench technologies, and moving them to larger size wafers. The auto industry is still pursuing high-temperature silicon, and researchers are actively pursuing the development of high-temperature SOI gate drivers to complement the silicon, notes Laura Marlino, deputy director of the power electronics and electrical power system research center at Oak Ridge National Laboratory. The center focuses on next-generation power electronics for the more electrified vehicles of the future. She also noted that the auto industry largely considers SiC still too expensive, but is starting to look more seriously at GaN for automotive applications.
Looking to New Manufacturing Processes to Enable Integration
Also coming to the power electronics world is a new level of integration, potentially reducing size and costs and improving energy efficiency by combining high-voltage devices with other functions on the same chip in relatively conventional CMOS process flows. One example: IBM Microelectronics' new foundry process combining high voltage capability, CMOS logic control and RF communication for smart wireless power management, aimed initially at enabling fine grain smart wireless monitoring and control of PV systems, building monitoring and control, and other sensor-based applications. “Power management is one of the key new opportunities we’re targeting. The integration of HV and RF function on one piece of silicon represents a new paradigm,” says James Dillon, IBM Systems and Technology Group.
IBM partnered with austriamicrosystems to add high voltage (12V-120V) capability to its RF on CMOS technology, optimizing the process to add only two additional mask layers, while maintaining the base 0.18µm CMOS/RFCMOS ground rules intact. The company says the process is about 20 percent lower in cost than the conventional BiCMOS/DMOS process typically used for power management chip, while providing system-on a chip functionality. The high-voltage FETS use triple-gate oxide CMOS and shallow trench isolation to reportedly get better on-resistance than the conventional BCD technology, without buried layers or epi. The company is currently running customer samples on multi project wafers.
Looking for New Packaging Solutions to Improve Thermal Management
The demanding automotive market is driving development in high-temperature packaging technology. “Packaging looks like the biggest opportunity now, the key enabler,” argues Oakridge’s Marlino.
One solution at International Rectifier and other companies to better thermal management is double-sided cooling, replacing wire bonding with closer coupling, by soldering the die to a metal heat sink, and adding another metal heat sink on top as well. “It opens up a whole new world to cool from both sides, changing the ways to design for thermal management from 2D to 3D, and means re-thinking the whole packaging system,” says Andrea Gorgerino, IR automotive applications engineer, noting the potential for continued improvement in power levels and current density from moving to high-current traces instead of wire bonds.
Technologies most likely to improve high-temperature chip package performance at low cost are to minimize or eliminate wire bonds, expensive materials and machined surfaces, and to simplify interconnect, noted Ralph Taylor at APEC,. Taylor is a staff development engineer at Delphi Electronics and Safety, who’s managing a DOE-funded project to develop a better power electronics system for electric or hybrid vehicles at lower cost by using the existing manufacturing infrastructure. Developers have replaced insulated-gate bipolar transistor (IGBT) modules with new discrete power packages on PCBs to allow double sided cooling. They aim to use the existing engine coolant system for power semiconductor cooling as well to reduce costs, though it runs at 105°C. Mixing high-temperature polycarbonate with a monomer doubles dielectric constant for better film capacitor performance at high temperature, but can still be extruded for low cost production with existing tools. Operating temperatures are also bumping up against the limits of die attach materials and encapsulants, where inorganic silicon gels with additives currently look like a possible solution.
“The EV/HEV market needs these high temperatures the most, so it’s driving the packaging innovation,” notes Alexandre Avron, analyst at Yole Développement, noting new approaches including micro particle silver paste, sintering and eutectic bonding now in production. Semikron is in production with its sintering approach, attaching die to substrate by a tricky manufacturing process of compressing silver powder at high heat and pressure. Using finer nanoparticle silver instead of the micro-particle powder could significantly reduce the time, temperature and cost of the process. Infineon is using eutectic soldering, or transient liquid phase bonding, where layers of Sn and Cu are stacked and heated so that the Sn diffuses through the Cu to create an alloy with a graded composition, which reportedly withstands temperatures up to 400°C or better.
SEMI is featuring a session on these emerging power semiconductor technology developments as part of the Extreme Electronics program on issues in emerging growth markets at SEMICON West 2011, on Tuesday, July 12.
SEMICON West 2011 Technical Program Webinar Replay Available
Confirmed speakers to date include experts from Freescale Semiconductor on the impact of vehicle electrification on power semiconductor technology, Yole Developpement [accent first e] on next technologies and trends in this growing market, Oakridge National Laboratory on high temperature packaging developments, International Rectifier on GaN issues, and SemiSouth on SiC technology.
Hear industry journalists and TechXPOT session coordinators David Lammers, Francoise Von Trapp and me review current critical technology issues and program agendas planned for SEMICON West 2011. The March 3 webinar is available now:
Exhibiting Opportunities Available
|Companies with innovative technologies and solutions are invited to exhibit at SEMICON West within the Extreme Electronics TechZONE. Close proximity to the presentation stage plus focused attendee marketing ensures high visibility with visitors focused on and interested in these technologies. Great opportunities are still available – learn more about exhibiting at SEMICON West and Extreme Electronics!|
April 5, 2011