Speaker: Prof. Joseph Bardin, UMass Amherst
Abstract:
In a variety of critical scientific fields, the highest performance instrumentation exploits cryogenically cooled electronics to achieve levels of performance far beyond what is feasible using room temperature electronics. For example, the free-space optical communications link—currently under development by NASA for Gbps communication with spacecraft—requires superconducting nanowire single photon detectors (SNSPD) operating at 1 K physical temperature to achieve sufficient earth terminal sensitivity. While much research has been focused on novel device technologies to enable new and more sensitive scientific instrumentation, limited work has focused on the use of semiconductor circuits to optimize the performance of these systems. In this talk, we will describe our research efforts in ultra-sensitive cryogenically cooled SiGe BiCMOS electronics for scalable scientific instruments. The talk will begin with a review of the physical performance limitations of SiGe HBTs at deep cryogenic temperatures (e.g., 4 K) and a discussion of modeling issues encountered by designers targeting this unconventional temperature range. We will then present the design, characterization, and system impact of novel circuits for a variety of applications ranging from THz focal plane arrays for radio astronomy to detector systems for quantum optics.