PORTLAND, Ore -- Downsizing big bulky terahertz (THz)detectors for integration on CMOS image chips has been accomplished by theUniversity of Texas (Dallas) with funding from the Semiconductor Research Corp(SRC). Accomplished under SRC's Focus Research Program, the demonstration ofterahertz speeds on standard CMOS opens a door for a new slew of consumerdevices that can see through solid objects.
"We can now build a CMOS image chip for acell-phone-sized camera module that sees in the terahertz range," said KenO, a professor and lead researcher for SRC's program at UT Dallas and a keyinvestigator in the Center for Circuit and System Solutions, a part of SRC'sFocus Center Research Program.
Today terahertz cameras are used, for instance, in theairport to see inside luggage and under clothing to detect hidden weapons, butthe devices require expensive discrete components. By downsizing terahertzsensors for standard CMOS chips, the terahertz camera can be both size and costreduced in the extreme.
"Inexpensive handheld terahertz cameras could be usedto detect counterfeit money or documents, to see inside envelopes or packages,or to find where the studs, wires and pipes are in walls," said O.
A one-pixel CMOSterahertz image chip (left) can see through solid objects, here showing theinner workings of an old-school floppy disk.The key to SRC's successful integration of terahertz imageron-a-chip is the discovery that high-speed Schottky diodes can be easilyfabricated in CMOS. Even at the relaxed design rules of130 nanometer used forthe demonstration chip, the high-speed Schottky diodes were able to achieveTHz-range performance without changing the standard CMOS processing steps.
"We have figured out how to create high-speed Schottkydiodes in CMOS without changing the process, just the layout," said O."We just take an active region where a transistor would normally go, anddon't draw the source-drain implantation mask layer, resulting in a Schottkydiode."
All the details on how to make terahertz image arrays usingSchottky diodes is presented in a paper entitled "280GHz and 860GHz ImageSensors Using Schottky-Barrier Diodes in 0.13μm Digital CMOS," at theInternational Solid-State Circuits Conference this week in San Francisco.
Many other application areas should be able to profit fromterahertz CMOS, which works as well as x-rays, but which are safe,non-destructive, and non-invasive. Besides terahertz cameras, the newhigh-speed Schottky diode process should also enable cheaper safer medicalscanners, cost-reduced security systems, and high-speed telecommunicationsapplications.
The results of all the technologies developed withSRC-funded projects are available to other members, which include AdvancedMicro Devices, Freescale Semiconductor, Globalfoundries, IBM, Intel, and TexasInstruments.
This story as originally posted by EETimes.
