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True Material Limit of Power Devices - Applied to 2-D Superjunction MOSFET

Accepted version
Peer-reviewed

Type

Article

Change log

Abstract

Predictions on limits of silicon in power devices have failed spectacularly in the past, but in spite of that, the theory that generated them is still used today and adapted for wide bandgap materials to justify their superior standing against silicon. The superjunction MOSFET was the first device to break by more than one order of magnitude the so-called ‘limit of silicon’ above 600V. The current theory of superjunction seems however to define a new technology based limit rather than a material based only limit. This implies that by scaling down the dimensions, in particular the cell pitch, the on-state resistances can continually decrease by several orders of magnitude, without a boundary. This paper shows that the down scaling of the cell dimensions cannot happen indefinitely and there is a material dependent intrinsic limit for any power device, which no longer is limited by the geometry or the technology available. Using an analytical approach, and backed up by advanced numerical simulations, we show that the minimum cell pitch is 0.18 μm for silicon and 0.05 μm for 4H-silicon-carbide, and further reduction in the cell pitch would result in an increase in the specific resistance. Finally, a new figure of merit for a superjunction MOSFET based on a rigorous 2D analysis is defined

Description

Keywords

Junction field-effect transistor (JFET), limit of superjunction (SJ), power devices, SJ

Journal Title

IEEE Transactions on Electron Devices

Conference Name

Journal ISSN

0018-9383
1557-9646

Volume Title

65

Publisher

Institute of Electrical and Electronics Engineers (IEEE)
Sponsorship
Engineering and Physical Sciences Research Council (EP/L007010/1)