Performance Enhancements of Low-Voltage LDMOS Power Switches by In-chip Integration of a Microcrystalline Diamond Substrate

Incorporation of a microcrystalline diamond layer in silicon chip substrates of 65-nm node n-LDMOS power switches presents a heat spreading effect that reduces hotspot temperatures. The extreme heat conductivity of diamond, 1500 W/(m*K), four time higher than copper and 10 times higher than silicon, reduces the thermal flux and hence the junction temperatures. The introduction of diamond layers displays a thermal short that drastically reduces temperature variations across the chip. Comparative characterization of LDMOS devices displays a 20–80 degree reduction in junction temperature when operated in saturation. A tripling in energy-handling capability for VIS switching mode is observed in a device where a microcrystalline diamond layer is integrated.