Search

A terahertz (THz) CMOS detector array based on multiple chips stitched together is reported. The proposed multichip detector is scalable as the total number of subarray chips is flexible and can be controlled as needed with the help of the modular scheme adopted. Based on the presented multichip technique, a $3\times $ 3 multichip detector array composed of nine subarray chips has been implemented in this work for operation at 300 GHz. With the subarray chips, each with $7\times $ 7 pixels, the complete multichip array comprises $21\times21$ physical pixels. By employing virtual pixels, which are included to compensate for the chip interface area consumed for interchip wire-bonding in this work, THz real-time images with $23\times23$ pixels have been successfully acquired. The distribution of the responsivity and noise equivalent power (NEP) over the multichip array is presented. The responsivity distribution shows the effect of the series resistance of the long bias lines stretched over the multichip array, while the effect is not apparent for NEP. The distribution due to series resistance, as well as other nonuniformities over the pixels and chips due to various causes, can be suppressed with a proper calibration for the images acquired with the multichip array. [ABSTRACT FROM AUTHOR]

We report, for the first time, the impact of proton irradiation on fourth-generation SiGe heterojunction bipolar transistors (HBTs) having a record peak unity gain cutoff frequency of 350 GHz. The implications of aggressive vertical scaling on the observed proton tolerance is investigated through comparisons of the pre-and post-radiation ac and dc figures-of-merit to observed results from prior SiGe HBT technology nodes irradiated under identical conditions. In addition, transistors of varying breakdown voltage are used to probe the differences in proton tolerance as a function of collector doping. Our findings indicate that SiGe HBTs continue to exhibit impressive total dose tolerance, even at unprecedented levels of vertical profile scaling and frequency response. Negligible total dose degradation in [beta] (0.3%), [[Florin].sub.T] and [[Florin].sub.max] (6%) are observed in the circuit bias regime, suggesting that SiGe HBT BiCMOS technology is potentially a formidable contender for high-performance space-borne applications. Index Terms--Breakdwon voltage, heterojunction bipolar transistors (HBT), proton tolerance, SiGe, silicon-germanium, technology scaling.

The relatively less exploited terahertz band possesses great potential for a variety of important applications, including communication applications that would benefit from the enormous bandwidth within the terahertz spectrum. This paper overviews an approach toward terahertz applications based on SiGe heterojunction bipolar transistor (HBT) technology, focusing on broad-band communication applications. The design, characteristics, and reliability of SiGe HBTs exhibiting record [f.sub.T] of 375 GHz and associated [f.sub.max] of 210 GHz are presented. The impact of device optimization on noise characteristics is described for both low-frequency and broad-band noise. Circuit implementations of SiGe technologies are demonstrated with selected circuit blocks for broad-band communication systems, including a 3.9-ps emitter coupled logic ring oscillator, a 100-GHz frequency divider, 40-GHz voltage-controlled oscillator, and a 70-Gb/s 4:1 multiplexer. With no visible limitation for further enhancement of device speed at hand, the march toward terahertz band with Si-based technology will continue for the foreseeable future. Index Terms--BiCMOS integrated circuits, communication systems, heterojunction bipolar transistors (HBTs), high-speed integrated circuits.

SiGe HBT transistoprs achieving over 200 GHz f[subscript gamma] and f[subscript MAX] are examined and reported.

P-type SiGe temperature-dependent minority electron mobilities have been measured.