Youichi Ashida

High Voltage and High Reliability Silicon-on-Insulator Power IC Technologies and Their Application to 750 V 4.5 A Micro-Inverter IC

We have successfully developed the record high blocking voltage of 750 V and the largest current capability of 4.5 A silicon-on-insulator (SOI) micro-inverter IC, which is made possible by the newly developed high voltage reliability technology and high-speed and low-dissipation extraction enhanced lateral insulated gate bipolar transistor (E2LIGBT). It has been found, for the first time, that the stable and reliable high blocking voltage of 760 V is assured by controlling the sheet-resistance of the polycrystalline silicon (poly-Si) layer of the scroll-shaped resistive field plate (SRFP). The high voltage and high reliability SOI power IC technology is expected as the key technology enabling 750 V 4.5 A micro-inverter IC for harsh applications such as automotive electronics.

Loss reduction of lateral power diode on SOI substrate with trenched buried oxide layer

We have investigated the static and dynamic characteristics of high voltage lateral power diode (L-Diode) on silicon-oninsulator (SOI) substrate with planar / trenched buried oxide (Box) layer on the basis of device simulations. The conduction loss of the conventional L-Diode with planar Box layer is found to be reduced as a result of improving blocking capability by trenching the Box layer. In addition, the switching loss of the conventional L-Diode with planar Box layer, which stems from the second peak of the recovery current, is substantially reduced by adopting the trenched Box layer with suppression of the dynamic avalanche phenomenon.

Extraction Enhanced Lateral Insulated Gate Bipolar Transistor: A Super High Speed Lateral Insulated Gate Bipolar Transistor Superior to Lateral Dobule Difused Metal Oxide Semiconductor Field-Effect Transistor

We have successfully developed novel extraction enhanced lateral insulated gate bipolar transistors (E2LIGBTs) in conventional silicon on insulator (SOI) wafers, which exhibit super-high speed switching of 34 ns turn-off time and a low on-state voltage of 3.7 V at 84 A/cm2 simultaneously with a high breakdown voltage of 738 V. This is the first report showing its superior switching speed and on-resistance compared to conventional lateral double diffused metal oxide semiconductor field-effect transistor (LDMOS). The superior performance is achieved by a new anode structure designed with the proposed E2 concept, which simultaneously achieves enhanced electron extraction and suppression of hole injection at the anode region without life time control. The E2 concept is realized using the anode structure, consisting of a narrow p+-injector and a wide Schottky contact on a lightly doped p-layer over an n-buffer. The switching speed can be controlled by the area ratio of the Schottky area over the injector area.