Power Semiconductor Devices Creating Comfortable Low-carbon Society

INTRODUCTION THE problem of global warming is an important issue for the entire world. At the Hokkaido Toyako Summit held in July 2008, with respect to the goal of achieving at least 50% reduction of global emissions by 2050, the USA and seven other major nations (the G8) leaders agreed to seek to share and adopt it with all parties to the United Nations Framework Convention on Climate Change, including the BRIC nations (Brazil, Russia, India, and China), to also adopt this target. Similarly, the government of Japan has proposed its Cool Earth Initiative and has announced its intention to “work toward establishing a low-carbon society that will be admired internationally with a long-term objective of reducing CO2 (carbon dioxide)emissions by 60 to 80% of current levels by 2050 as Japan’s contribution to the goal of halving total global emissions by 2050.” In recent years, the concentration of CO2 in the atmosphere has reached levels higher than any the Earth has experienced over the last 600,000 years (see Fig. 1). The major cause of this rise is the extensive use of fossil fuel since the industrial revolution and the IPCC (Intergovernmental Panel on Climate Change) Fourth Assessment Report released in 2007 predicted that by 2100 the mean global temperature could rise by up to 6.4°C and sea levels by up to 59 cm. This article describes the expectations for power semiconductor devices in their role as key devices in power electronic equipment for achieving a lowcarbon society with a halving of CO2 emissions by 2050, and also looks at the potential market size. The article also looks at IGBTs (insulated gate bipolar transistors), a type of power semiconductor devices that has experienced annual growth of 19% in recent OVERVIEW: Reducing CO2 emissions recently has been an urgent issue to cope with the global warming. As the G8 leaders at the Hokkaido Toyako Summit in 2008 agreed to seek to share and adopt “the goal of achieving at least 50% reduction of global emissions by 2050” and the Japanese government set “the long-term goal of reducing 60 to 80% of emissions by 2050,” there is a need for greater energy conservation and a switch to sustainable energy sources that do not use fossil fuels. Power electronics equipment and power semiconductor devices will be key for achieving these goals. Hitachi has been developing new power semiconductor devices, primarily through collaboration and cooperation with power electronics departments in the fields of power generation, rolling stock, automotive vehicles, industry, and consumer electronics. This report estimates the market size of the power semiconductor devices in a low-carbon society with a “halving of CO2 emissions.” It also describes Hitachi’s latest technology of power semiconductor devices and the role of these devices in the future.