Study on InGaAs-On-insulator HEMTs on Si CMOS for monolithic 3D integration

Abstract

For the monolithic 3-dimensional (M3D) integrated low-noise analog-digital mixed-signal system, we present an InGaAs high-electron-mobility transistors (HEMTs) on Si CMOS. First, to develop the process module for the M3D stacked InGaAs HEMT, we have demonstrated 125-nm-gate InGaAs-on-insulator (InGaAs-OI) HEMTs on bare Si substrates via wafer bonding. The highlights of this device were the $i-In_{0.53}Ga_{0.47}As/i-InAs/i-In_{0.53}Ga_{0.47}As$ quantum-well channel for high RF performance by improving electron transport properties and the low processing temperature of 250 °C or less for M3D integration. Then, we successfully demonstrated high-frequency InGaAs HEMTs integrated on 180 nm Si CMOS using the developed process module without any device performance degradation. As a result, we obtained a current gain cutoff frequency ($f_{T}$) of 289 GHz and maximum oscillation frequency ($f_{MAX}$) of 195 GHz. These results are the highest ever reported in M3D RF transistors at the same LG range. Finally, we have analyzed the effect of substrate coupled digital noise in both conventional and M3D mixed-signal systems. Through this analysis, we found that the influence of substrate digital noise can be eliminated by integrating the analog and digital circuits in the M3D platform. This will be the important milestone and one of the breakthrough technology in high-frequency mixed-signal IC.