9 research outputs found
Silicon-Germanium Bipolar Technology for Enabling Cold-Capable, Radiation-Tolerant Electronics for Spacecraft
The objective of this research is to investigate the effect that low temperature has on the
radiation effects on advanced silicon-germanium (SiGe) heterojunction bipolar transistor
(HBT) for the application of deep-space exploration missions that are specifically classified
as extreme low-temperature and highly radiation active environments, such as Jovian
exploration missions. We designed a unique experimental testbed that enabled DC and RF
measurements to be taken in situ at various temperature and radiation points. The experiment
was conducted at the Jet Propulsion Laboratory (JPL) where low-temperature and
radiation environments can be mimicked. We showed that while there is some radiation
damage in base leakage current on the single transistor level, there is no observed damage
due to total-ionizing dose (TID) in noise figure, linearity, or gain for a 2.4 GHz low-noise
amplifier (LNA) that was irradiated at an ambient temperature of about 100 K up to 1 Mrad
(Si). Furthermore, we confirmed the notion that radiation at lower temperatures yields less
damage and showed why it is important to separate temperature-dependent performance
with measurable radiation damage at different temperatures.
We also took a simulation approach to determine whether single-event transients (SETs)
get worse as a result of the device being in low ambient temperatures. For a single standalone
device, the results show that the transient gets larger in magnitude but shorter in
duration. However, the circuit results show that the effects of an SET get worse in some
cases with low temperatures such as in the context of LNAs, but can also get better in other
cases such as current-mode logic (CML) D-flip-flops.M.S
Integrated Silicon Photonics for Enabling Next-Generation Space Systems
A review of silicon photonics for space applications is presented. The benefits and advantages of size, weight, power, and cost (SWaP-C) metrics inherent to silicon photonics are summarized. Motivation for their use in optical communications systems and microwave photonics is addressed. The current state of our understanding of radiation effects in silicon photonics is included in this discussion. Total-ionizing dose, displacement damage, and single-event transient effects are discussed in detail for germanium-integrated photodiodes, silicon waveguides, and Mach-Zehnder modulators. Areas needing further study are suggested