This study introduces the development advances and trend of power semiconductors used in hybrid and electric vehicles (HEV/EV). The status and forecast of power electronics’ requirement in HEV/EV are discussed along with a review of the automotive standard of power semiconductor devices. The advances in automotive semiconductor technologies such as Si-based insulated-gate bipolar transistor (IGBT) and freewheeling diode (FRD) and SiC-based metal oxide semiconductor field-effect transistor (MOSFET) and Schottky barrier diode are presented. The advances in automotive semiconductor packaging technologies are illustrated from three considerations, which are the low inductance in high-power density packaging, lower thermal resistance designing, and advanced packaging technologies. The challenges and development trend of more reliable power semiconductors for HEV/EV are discussed. The challenges in Si devices are focused on power density, efficiency, reliability, and packages, while the high temperature and low inductances are the main challenges for SiC devices. Lastly, the development trend is discussed in terms of four aspects, the new generation Si IGBT for HEV/EV, such as recessed-emitter-trench, reverse-conduction-IGBT, and smart IGBT; next generation SiC MOSFET; new packaging technology and material, such as planar packaging.

This work presents a hybrid 3.3 kV/450 A insulated-gate bipolar transistor (IGBT) power module, utilising the half-bridge topology. In contrast to the traditional fashion, each IGBT chip in this module is allocated with two anti-parallel silicon carbide (SiC) Schottky barrier diodes (SBDs). Each SBD describes smaller footprint than the conventionally used silicone (Si) based fast recovery diode at this voltage and current level. By adopting smaller SiC SBDs in this hybrid-style packaging structure, the SBD chip yield can be greatly improved, without any additional fabrication cost. To benchmark the advantages of this hybrid power module over the Si-based counterpart, both power modules are designed, fabricated as well as tested statically and dynamically. It is shown that while both types show similar thermal behaviour, the hybrid power module describes much lower IGBT turn-on current overshooting, diode reverse recovery loss and IGBT turn-on loss. Based on the measured results, the power losses of both modules under a three-phase inverter operation condition are calculated, showing that the hybrid module has considerably lower power losses and junction temperature rise.

Medium voltage power supplies for applications such as electrostatic precipitators are used in industrial plants to remove particles from fumes. Current solutions based on silicon devices rely on high-voltage transformers to reach the required output voltage levels. New wide band gap materials such as silicon carbide have higher electric breakdown voltage, and thus fewer devices are required in series to withstand the output voltage. Owing to the faster switching speed of silicon carbide devices further demands are put on the serialisation method. In this study, a cascaded series-connection method using only a single external gate signal is analysed in detail, guidelines to size the resistor–capacitor–diode-snubber are proposed and its applicability is experimentally demonstrated. The circuit is tested with four series-connected devices in a double pulse test at 2400 V and current levels of 250–800 mA to show the load dependence. The serialisation technique is tested in a boost converter operating in discontinuous conduction mode but is limited to 1200 V due to an oscillating state occurring after zero current crossing. Finally, the technique is tested at 2400 V and 10 kHz in a synchronous boost converter, which demonstrates the proposed design guidelines.

High-temperature electrical performances of enhancement-mode (E-mode) high electron mobility transistor with p-type Gallium Nitride (GaN) gate cap are evaluated here. The physics-based mechanisms behind the behaviours are also analysed by the simulations and analytical models. For static electrical performances, the changes of GaN bandgap and the interface states or traps are considered to be influential factors for the little variations of threshold voltage (V_T ). Meanwhile, the on-state resistance increases and trans-conductance decreases at high temperatures due to the reduction in electron mobility (µ _eff). As for blocking characteristic, high temperature-induced increase of leakage current may result from multi-reasons, such as the increase of intrinsic carrier concentration and lowering of trap barrier. In addition, a segmental method is presented to understand the gate leakage current at high temperatures. For capacitance characteristics, the increase of channel resistance makes the measured gate capacitance lower than the intrinsic value. For dynamic electrical performances, the high temperature-induced decrease of µ _eff leads to the increase of plateau voltage, bringing the decreases of total switching time and total switching energy loss, which are quite different from those of the devices with traditional metal-oxide-semiconductor structures.