Impact of Device Scaling on Phase Noise in SiGe HBTs UWB VCOs

The performance of the electronic system strongly depends on the speed of devices, and technological scaling has driven this momentum towards achieving faster speed and high level of integration. Device scaling has been the principal driving force behind the technological innovations, and breakthrough of the past century. This paper investigates the impact of device scaling on oscillator/VCO phase noise in SiGe HBTs, which has recently emerged as a strong contender for RF and mixed signal applications. The relative contribution of the broadband (thermal and shot noise) and low frequency (1/f noise) noise sources are examined with respect to the device scaling. An approach of minimizing the phase noise with respect to the scaling is discussed, and demonstrated for distributed coupled resonator (DCR) based ultra wideband (UWB) VCOs. The measured phase noise is typically -115 dBc/Hz at 100 kHz offset over the tuning range (2-6 GHz), and to our knowledge, this is the best phase noise performance for this band using printed multi-coupled resonator with SiGe HBT (Infineon BFP 740) so far reported