(Invited) Integration of an Epitaxial-Base-Link HBT Device with fT = 300GHz, fmax 480GHz in 90nm CMOS

Abstract

SiGe HBT based BiCMOS technologies have found widespread use in millimeter-Wave (mmW) applications such as high-speed communication and automotive radar, but are also receiving increased attention for operating frequencies above 100GHz. The drive for higher operating frequencies while reducing power consumption continues to fuel the development of new BiCMOS technologies with HBTs featuring higher switching speeds (fmax) integrated with smaller, more power efficient and cost effective CMOS nodes. There is strong evidence however, that in volume production double poly self-aligned (DPSA) HBT architectures may be limited to fmax of 400GHz[i],[ii],[iii],[iv],[v],[vi]. Alternative HBT architectures to overcome this limitation have been proposed[vii],[viii],[ix].In this paper we report the successful integration of a SiGe HBT module with fT = 300GHz, fmax = 480GHz in a 90nm BiCMOS technology platform. Building on previous studies by IHP[x] and Infineon[xi] the Epitaxial-Base-Link process flow was further adapted for compatibility to the 90nm CMOS base technology. The new technology platform features seven Cu metal layers high quality passives including a TaN resistor and a MiM capacitor positioned between metal levels 6 and 7 for low parasitic substrate coupling. One metal layer was added compared to the 130nm platform to facilitate the transition from thin wire to RF metallization.Figure 1 shows a TEM cross section of one of the first successful 90nm BiCMOS runs. Key challenges of the integration into the new CMOS node will be summarized in the presentation. The same device showed nearly ideal Gummel characteristics. CML ring oscillators with a design width EW of 190nm and 2.8 µm length achieved a wafer mean gate delay of 1.86ps with a standard deviation of 1.9%.Acknowledgment: This work was supported by the European Commission and the German Federal Ministry of Education and Research (BMBF) under project ref# 16ESE0202S ECSEL-TARANTO. [i] V. P. Trivedi et al., “A 90nm BiCMOS Technology featuring 400 GHz fMAX SiGe:C HBT”, in Bipolar / BiCMOS Circuits and Technology Meeting, 2016, pp. 60-63. [ii] V. Jain et al., “Device and circuit performance of SiGe HBTs in 130nm BiCMOS process with fT/fmax of 250/330GHz,” IEEE Bipolar/BiCMOS Circuits and Technology Meeting, 2014, pp. 96-99. [iii] P. Chevalier et al., “A 55 nm triple gate oxide 9 metal layers SiGe BiCMOS technology featuring 320 GHz fT / 370 GHz fMAX HBT and high-Q millimeter-wave passives,” in International Electron Devices Meeting (IEDM), 2014, pp. 3.9.1-3.9.3. [iv] J. Pekarik et al., “A 90nm SiGe BiCMOS technology for mm-wave and high-performance analog applications,” in IEEE Bipolar/BiCMOS Circuits and Technology Meeting (BCTM), 2014, pp. 92–95. [v] P. Hurwitz, R. Kanawati, K. Moen, E. Preisler, S. Chaudhry and M. Racanelli, "Advances in RF foundry technology for wireless and wireline communications," 2016 IEEE 16th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF), Austin, TX, 2016, pp. 5-8. [vi] J. Böck et al., “SiGe HBT and BiCMOS process integration optimization within the DOTSEVEN project”, in Bipolar / BiCMOS Circuits and Technology Meeting, 2015, pp. 121-124. [vii] Q. Z. Liu et al, “SiGe HBTs in 90nm BiCMOS Technology demonstrating fT / fmax 285GHz / 475GHz through simultaneous reduction of base resistance and extrinsic collector capacitance”, ECS transactions, 64(6) , 2014, pp. 285 – 294. [viii] A. Fox, B. Heinemann, R. Barth, S. Marschmeyer, C. Wipf and Y. Yamamoto, "SiGe:C HBT architecture with epitaxial external base," 2011 IEEE Bipolar/BiCMOS Circuits and Technology Meeting, Atlanta, GA, 2011, pp. 70-73. [ix] V.T. Vu, D. Celi, T. Zimmer, S. Fregonese, P. Chevalier, “Advanced Si/SiGe HBT architecture for 28-nm FD-SOI BiCMOS”, in Bipolar / BiCMOS Circuits and Technology Meeting, 2016, pp. 64-67. [x] B. Heinemann et al., "SiGe HBT with fx/fmax of 505 GHz/720 GHz," 2016 IEEE International Electron Devices Meeting (IEDM), San Francisco, CA, 2016, pp. 3.1.1-3.1.4. [xi] D. Manger et al., "Integration of SiGe HBT with fT=305 GHz, fmax=537GHz in 130nm and 90nm CMOS," 2018 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS), San Diego, CA, 2018, pp. 76-79. Figure 1