In this paper, we present a mixed-technology micro-system for electronically manipulating and optically detecting virusscale
particles in fluids that is designed using 3D integrated circuit technology. During the 3D fabrication process, the
top-most chip tier is assembled upside down and the substrate material is removed. This places the polysilicon layer,
which is used to create geometries with the process' minimum feature size, in close proximity to a fluid channel etched
into the top of the stack. By taking advantage of these processing features inherent to "3D chip-stacking" technology,
we create electrode arrays that have a gap spacing of 270 nm. Using 3D CMOS technology also provides the ability to
densely integrate analog and digital control circuitry for the electrodes by using the additional levels of the chip stack.
We show simulations of the system with a physical model of a Kaposi's sarcoma-associated herpes virus, which has a
radius of approximately 125 nm, being dielectrophoretically arranged into striped patterns. We also discuss how these
striped patterns of trapped nanometer scale particles create an effective diffraction grating which can then be sensed with
macro-scale optical techniques.
We present an alternative signaling method for multi-channel fiber ribbon based optical links. The method is based on a hybrid of differential signaling and single-ended channels. Channels are grouped into code blocks of n-bits. Each code word transmitted in the block is restricted to conform to an n choose m rule. Electrical drivers steer current between m active VCSELS with no dummy loads. A virtual reference is synthesized from the received signals and used for differential discrimination. This signaling method approaches the signal-to-noise characteristics of fully differential signaling but can be implemented with significantly lower channel overhead, giving as much as a 33% reduction in fiber count and a 44% reduction in power. Further, code utilization rates on these links can be as low as 51%, leaving substantial code space available for ECC or channel management functions. In this paper, we describe the signaling method and present a prototype transceiver chip. The transceiver is implemented in 0.25um UTSi Silicon-on-Sapphire technology with flip-chip bonded VCSEL and photodetector arrays. The design demonstrates a pin-compatible alternative to the POP4-MSA transceiver standard with 125% greater data throughput and 25% better power efficiency.