Advancements in 300 mm GaN-on-Si Technology With Industry’s First Circuit Demonstration of Monolithically Integrated GaN and Si Transistors

Advancements in 300 mm GaN-on-Si enhancement-mode (E-mode) GaN N-MOSHEMT technology featuring monolithically integrated Si pMOS by layer transfer are presented. In this work, a true gate-last flow is employed, where the high-temperature activation steps of the Si pMOS transistors are completed before depositing the gate dielectric of the GaN N-MOSHEMT. In addition to the Si pMOS integration, GaN N-MOSHEMT performance is enhanced with an $f_{\mathrm{MAX}}$ of 335 GHz ( $L_{G}$ $=$ 90 nm). A mmWave power amplifier (PA) with a high area power density of 3.11 W/mm $^{2}$ and 99.1 dB figure-of-merit is demonstrated using the improved GaN N-MOSHEMT. Employing GaN N-MOSHEMT and Si pMOS, a vector modulator-based mmWave phase shifter with a 5-bit current-controlled digital-to-analog converter (DAC) is designed and fabricated in this process. The phase shifter achieves full functionality with 360 $^{\circ}$ phase tuning coverage, 5.3 $^{\circ}$ measured RMS phase error, and less than $\pm$ 1.7 dB magnitude variation across different phase states, occupying 0.12 mm $^{2}$ . This is the industry's first demonstration of a complex monolithic GaN-Si CMOS circuit, implemented in 300 mm GaN-on-Si technology.