Compared　with　silicon　and　silicon　carbide　devices,　the　unique　electrical　and　structural　characteristics　of　gallium　nitride　high　electron　mobility　transistors　(GaN　HEMTs)　make　them　have　different　requirements　for　power　module　integration.　This　article　proposes　a　novel　integration　scheme　for　the　high-voltage　lateral　GaN　HEMT　dies　without　bonding　wires.　Based　on　the　proposed　integration　scheme,　a　compact　650　V/30　A　GaN　power　module　with　low　parasitic　parameters　and　high　thermal　performance　is　designed.　The　GaN　dies　are　sandwiched　between　two　ceramic　substrates　to　improve　thermal　performance　and　ensure　consistent　thermal　expansion　coefficients.　The　multiple　copper　layer　structure　is　used　to　increase　wiring　flexibility　to　reduce　parasitic　parameters.　The　design　of　gate　and　power　loop　layouts　is　discussed,　and　the　common-mode　(CM)　capacitance　is　optimized.　A　comprehensive　reliability　evaluation　is　also　carried　out　for　this　integration　scheme.　Finally,　a　double-sided　cooling　650　V/30　A　full-bridge　GaN　power　module　with　2.4　cm×1.3　cm×0.17　cm　is　fabricated.　The　thermal　resistance　is　reduced　by　30%-48%　compared　with　the　conventional　single-sided　cooling　module.　The　power　loop　and　gate　loop　inductances　are　reduced　to　0.94　nH　and　2　nH,　respectively,　and　the　CM　capacitance　is　limited　to　2.5　pF.　The　maximum　dv/dt　of　the　drain-source　voltage　is　high　as　150　V/ns　with　only　10%　overshoot.　Based　on　the　power　module,　a　3.3-kW　two-phase　interleaved　buck　converter　is　developed.　It　has　820　W/in3　power　density　and　98.85%　peak　efficiency.　©　1986-2012　IEEE.