ISSCC: UT Dallas Shows Single-Chip Terahertz Imager

EETimes: "We can now build a CMOS image chip for a cell-phone-sized camera module that sees in the terahertz range," said Ken O, a professor and lead researcher at UT Dallas. The key to integration of terahertz imager on-a-chip is the high-speed Schottky diodes fabricated in CMOS. "We have figured out how to create high-speed Schottky diodes in CMOS without changing the process, just the layout," said O. "We just take an active region where a transistor would normally go, and don't draw the source-drain implantation mask layer, resulting in a Schottky diode."

Even at design rules of 130nm used for the demonstration chip, the high-speed Schottky diodes were able to achieve THz-range performance without changing the standard CMOS processing steps.

A one-pixel CMOS terahertz image chip (left) can see through solid objects,
here showing the inner workings of an old-school floppy disk.

The details are presented in a paper "280GHz and 860GHz Image Sensors Using Schottky-Barrier Diodes in 0.13µm Digital CMOS," at the ISSCC this week in San Francisco.

Another similar paper at ISSCC is "A 1kPixel CMOS Camera Chip for 25fps Real-Time Terahertz Imaging Applications" by STMicro, Crolles, France, University of Wuppertal, Wuppertal, Germany and IEMN / ISEN, Lille, France