D. Smith

High Performance Mixed Signal and RF Circuits Enabled by the Direct Monolithic Heterogeneous Integration of GaN HEMTs and Si CMOS on a Silicon Substrate

In this work we present recent results on the direct heterogeneous integration of GaN HEMTs and Si CMOS on a silicon substrate. GaN HEMTs whose DC and RF performance are comparable to GaN HEMTs on SiC substrates have been achieved. As a demonstration vehicle we designed and fabricated a GaN amplifier with pMOS gate bias control circuitry (a current mirror) and heterogeneous interconnects. This simple demonstration circuit is a building block for more advanced RF, mixed signal and power conditioning circuits, such as reconfigurable or linearized PAs with in-situ adaptive bias control, high power digital-to-analog converters (DACs), driver stages for on-wafer optoelectronics, and on-chip power distribution networks.

A high performance differential amplifier through the direct monolithic integration of InP HBTs and Si CMOS on silicon substrates

We present results on the direct monolithic integration of III–V devices and Si CMOS on a silicon substrate. InP HBTs (0.5 × 5 um2 emitter) with ft and fmax ≫ 200GHz were grown directly in windows adjacent to CMOS transistors on silicon template wafers or SOLES (Silicon on Lattices Engineered Substrates). A BCB based multilayer interconnect process was used to interconnect the InP HBT and Si CMOS to create a differential amplifier demonstration circuit. The heterogeneously integrated differential amplifier serves as the building block for high speed, low power dissipation mixed signal circuits such as ADCs and DACs.

Progress and challenges in the direct monolithic integration of III–V devices and Si CMOS on silicon substrates

We present results on the direct monolithic integration of III–V devices and Si CMOS on a silicon substrate. Through optimization of device fabrication and material growth processes III–V devices with electrical performance comparable to devices grown on native III–V substrates were grown directly in windows adjacent to CMOS transistors on silicon template wafers or SOLES (Silicon on Lattices Engineered Substrates). While the results presented here are for InP HBTs, our direct heterogeneously integration approach is equally applicable to other III–V electronic (FETs, HEMTs) and opto-electronic (photodiodes, VSCLS) devices and opens the door to a new class of highly integrated, high performance, mixed signal circuits.

Molecular Beam Epitaxy Growth of High Mobility Compound Semiconductor Devices for Integration with Si CMOS

We report on a direct epitaxial growth approach for the heterogeneous integration of high speed III-V devices with Si CMOS logic on a common Si substrate. InP-based heterojunction bipolar transistor (HBTs) structures were successfully grown on patterned Si-on-Lattice-Engineered-Substrate (SOLES) substrates using molecular beam epitaxy. DC and RF performance similar to those grown on lattice-matched InP were achieved in growth windows as small as 15×15μm 2 . This truly planar approach allows tight device placement with InP-HBTs to Si CMOS transistors separation as small as 2.5 μm, and the use of standard wafer level multilayer interconnects. A high speed, low power dissipation differential amplifier was designed and fabricated, demonstrating the feasibility of using this approach for high performance mixed signal circuits such as ADCs and DACs.