MUCH - A MOS-Like Switch for Smart Power

A novel mutual channel (MUCH) device for switching high voltage on a small chip area is presented. The device layout is composed of two interacting MOS-transistors. The two transistors are stacked on each other and separated by a shared gate oxide. By this concept idea, a mutual channel device with beneficial high voltage behaviour and without any ordinary drift region can be designed. Simulation results show that, for the same breakdown voltage and on-resistance, 3-9 times smaller chip area is needed for the proposed concept compared to a transistor made in ordinary LDMOS technique. Experimentally, the voltage breakdown for a 30 μm long n-channel and a 10 μm long p-channel, separated wit 490 Å thick gate oxide, is measured to 180 V. The on-resistance for the same device is about 1.5 kΩ/sq.