GaN-on-Si HEMTs Fabricated With Si CMOS-Compatible Metallization for Power Amplifiers in Low-Power Mobile SoCs

• Published in: IEEE microwave and wireless components letters Vol. 31; no. 2; pp. 141 - 144
• Main Authors: Xie, Hanlin, Liu, Zhihong, Hu, Wenrui, Zhong, Zheng, Lee, Kenneth, Guo, Yong-Xin, Ng, Geok Ing
• Format: Journal Article
• Language: English
• Published: IEEE 01.02.2021
• Subjects: Gallium nitride; GaN-on-Si; HEMTs; high electron mobility transistor (HEMT); Logic gates; mobile system-on-chip (SoC); MODFETs; Ohmic contacts; Radio frequency; Silicon
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2020.3036389

GaN-on-Si high electron mobility transistors (HEMTs) were fabricated using Si CMOS-compatible metallization scheme for RF power amplifiers (PAs)in 5G low-power mobile system-on-chips (SoCs). Ta/Al metals were adopted for the ohmic contact formation. The device with 80-nm rectangular gate exhibited a drain current (<inline-formula> <tex-math notation="LaTeX">I_{d\mathrm {max}} </tex-math></inline-formula>) of 1.95 A/mm, a peak transconductance (<inline-formula> <tex-math notation="LaTeX">g_{m} </tex-math></inline-formula>) of 471 mS/mm, a cutoff frequency (<inline-formula> <tex-math notation="LaTeX">f_{T} </tex-math></inline-formula>) of 178 GHz, and a maximum oscillation frequency (<inline-formula> <tex-math notation="LaTeX">f_{\mathrm {max}} </tex-math></inline-formula>) of 74 GHz. At a mobile SoC-compatible supply voltage of <inline-formula> <tex-math notation="LaTeX">V_{d} = 5 </tex-math></inline-formula> V, the device shows a peak power-added efficiency (PAE) of 51.4%/47.6%, a maximum output power density (<inline-formula> <tex-math notation="LaTeX">P_{\mathrm {outmax}} </tex-math></inline-formula>) of 1.12 W/mm/1.06 W/mm, and a gain of 16 dB/16 dB at frequency of 3.5 GHz/5 GHz, respectively. These results indicate the great potential of the GaN-on-Si HEMTs for high-performance and low-cost RF PAs for 5G mobile SoC applications.