@ Electronic Components and Circuits o Electronic Systems @ Physical Sciences S Materials e Computer Programs e Mechanics Machinery = Fabrication Technology 0 Mathematics and Information Sciences “) Life Sciences 99-10 October 1999 pW -WI5558 (O ) ‘Tech Briets are short announcements of innovations originating from research and Gevelopment activ- ites of the National Aeronautics and Space Administration. They empha: ze information considered likely to be transferable across industrial, regional, or Giscipinary ines and are issued to encourage commercial application. Availability of NASA Tech Briefs and TSPs Requests for individual Tech Briefs or for Technical Support Packages (TSPs) announced herein shobe uacolressded to National TechnToranlsfoer gCeynt er TelephonNeo . 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StenSpnacei Csen ter “"*” ” -™ Hank Davis Kirk Sharp Gerald Johnson (281) 483-0474 or (228) 688-1929 or Office ofA eronautics (Code FR; hdavis@gp 101 ysc.nasa.gov ksharp@ssc nasa gov (202) 358-4711o r [email protected]. nasa.gov NASA Tech Brnets, October 1999 NASA Tech Briefs, October 1990 Q 15 Electronic Systems A” w 25 Physical Sciences © 31 Materials S 35 Computer Programs eS 39 Mechanics ve 43. Machinery «3 49 Fabrication Technology - 53 Mathematics and Information Sciences >, This Gocunent was prepared under the sponsorship of the National Aeronautics and Space Administration. Neithte Uhniteed rSta tes Government nor any person acting on behalf of the Unmed States Government assumes any liability resulting from the use of the information contained in this document, or warrants th71 such use wil be free from privately owned nights PARK PAG Electronic Components and Circuits Hardware, Techniques, and Processes 7 Active-Pixel-Sensor ICs With Photosites in Substrates 8 GaN-Based Linear Array of Ultraviolet Detectors u integrated infrared- and Visible-image Sensors 10 inflatable Refiectarray Antennas 10 Filtering To increase Effective Yields of image Sensors 11 Frequency-Scanning Capacifiectors 12 Hybrid Imaging Technology 13 High-Speed image Detectors With Subelectron Noise Floors kK improved Contro! of Charging Current for Ni/H Battery NASA Tech Bnefs. October 1999 i. OA AMA? HAP LIS Active-PICis xWiteh lPho-tosSitees nin sSubostrrat es Heretofore, SOl CMOS has been considered NASA's Jet Propulsion Laboratory, unsuitable for APS circuits. Pasadena, California Focaalrray-s pof lactvae-pnoe!e s er sors (photodetectors miegaied wih n- - One Pow pixel readout transistors) would be Voo ~? designed and fabricated within the emero- ng tectnoiogcal disopiine of slicon-c Revet-—p a insulator (SO) complemenmettaal ronyd e semico(CnMOSd) uintecgrattedo crroui ts 0Cs), according to a proposal. SO! OMOS seems dasined to suppiatt the mow tanfiar buk CMOS as the standard for fabrication of very-large-ismecgaralteed (VLS) circuits, Guring the next few years. Heret thaso beefn goenerralley c,ons id- ered that functional APS circults cannot be impleinm SOe! OnMOtS ebecdau se the layers of silicon for fabricatielnegc - tronic Gevices on SO! wafers are so thin that optical absorbing volumes cannot be made large enough. in the proposed approach, photodeter ss woubel imdpie - mentwieth dS Ol on subsraiesi n Such @ way as to obusn the desired func- tionality. Little or no departure from estab- ished SO! CMOS processwoiulnd gb e neceOne sdisasdvanatagre oyf SO.! mi ght be @ tendency toward the floating-body effect, but iti s possible to counteract this structure, ‘he planar character would, — SON add ST heedF ON -——-—s ee eee ee oe ee ---—-—-—————— = = = «= noated HONG Wit) CMe SUDSIUCLIES — These Cross Sections (nc! 1 scsie) represent unitc olso ft woo fs everal APSd esigns proposed by stancaard SO! fabrication techniques. 20 be implemented ir, SO! CMOS: woud be lower because the substrate ¢ Complementary transistors would be reset al the way to the power-supply capacitance would be lower Lower placed ir each pixel to obtain high voltage (Vi,). Iti s not possible toi ncor- sensing-node capacitance would trans- Gynec range. A metal oxide sernicor)- porate such @ structure into an APS in late to higher Conversion gain and lower Guctor baki-effect-tranaistor with p dop- buk CMOS without adversely affecting noise, and thus the ability to detect light ing (MOSFET) would be incorporated the pow! size and increasing the poten- at lower levets for uS® 4S @ reset gate that would enable tal for latch-up, but fti s possibie in SO! NASA Tech Brets, October 190% 7 CMOS because SO! transistorasr e formed in isolated islands. © Cross-taikk would be reduced because parasitic capacitwoaulnd cbee lsow er © Photodetin-epicxeli coircruitsry,, a nd) =s._-«~P ain of Caltech for NASA's Jet Propul- and because of the isolation of individ- pericropuithry ewourld aal lexh bt sion Laborfuarhet noorrmayn s ual transistors. Qreater radiation harchess because sl- contarTxSPx f/seei pnagea 1) @ in the absence of substrate coupling, con layers woud be thinner and because NPO-20534 timing patterns could be Changed to of the prevention of fieid-assisted enable the sirnultaneous operation of increase in dak current mentioned GaN-Based Linear Array of Ultraviolet Detectors This is a solar-blind array that can operate at GodSdpacea Flirght dCent er, room temperature. it _-———— rom a : 1 1" w a ee Veni Figure 2. The Reaponsofi Onve iDetteycto r Elernent was measured during operation at a potential under 10 V. Note the sharp custo at the wavelenofg 3t70h n m. necting lines were formed in a TVAVAu multilayer, which was used to ensue good ohmic contact. Figure 2 shows the measured responsiv- ity of one Getector element. This detector @ement was found to have a responsivityo f 3.1 2 0.3 AW ata wavelength of 365 nm, a response time of 0.5 + 0.2 ms, and a dark current of 5 x 10°"' A as of the time of sub- mission of the informfoar ttiis oa@tnick e, Figure 1 The Array Contains 16 Elements. each having an imterdgtates metai/semrconductor these perfofirgurmes awerne cthee be st structure with 20 fingers coming in from each end. The fingers are spaced at intervals of 4 ym. yet reported for GaN uitraviolet detectors. Each finger is 2 um wide and 500 ym long. There are numerous potential industri- al, medical, and scientific-reseaarppcihi - A recently developed galun nitride plates Now used tc detect ultraviolet light cations for GaN detector arrays like this based inear array of ultraviolet detectors is This GaN detector array also operates at one. For example, because of their solar- blind to most of the visible spect, with lower voltage. MoreoGavN ies rrug,ged , blind nature, such arrays would be well @ Cutoff wavelength of 370 nn. This device av! the fabrication of detectors from GaN sulted for geophysical observation. They iS @ prototype of GaN detector arays for (Sr elatively easy could also be used to detect ulraviclet Utravomaglineg 1t t-hei pragsahnnet o f - The prototype device —— a 1 x 16 array light in hot environamnde tnr, tdestec t sig icant visible radiation, without need for — was fabricated by a conventioniiaftl-o f ultraviolet emissions from flames and extensive baffing to suppress stray ight or technique. Each detector element com- rocket exhausts. for costly Mars to biock visible ight. The prises a metal/semiconductor/meinttaer - This work wes done by Zhenchun (agitated structure (see Figure 1) The Huang, David Brent Mott, and Peter K. Overall area of the array is 4 mm. Sem. Shu of Geddard Space Flight Center insulating GaN was used to obtain iow No turther documentaist aivaoianbl e Gark current. The metal digits and con- GSC- 13828 NASA Tech Bnets. October 1999 N@s mvoived splitting of the optical path mito an infrared and a visible branch, each Cortaining @ separate image sensor opt- mized for fs wevelreanngeg. tinh co n- ast, each of the proposed image sensors would include pixel detectors for both wavreangels, aend snensogrs cnould be Gesigned to operate with or without spit- ting of optical paths. The figure dustratefisv e alternative Gesign concepts for the proposed Concept is similar to the first one, except that the visibldeteec-toris gwohultd be implein am hyebrind sttrucetured. The visidie-readout portion of the multiplexer Circuttry Could be similar to the infrared- readout portion, or itc ould be designed @S @ photoelectron-counctiricnulgt . The third, fourth, and fifth concepts do not ental spitting of the optical path According to the third concept, the visible and infrared pixel detectors would be inter- Spersed throtuhe gsanhe oimauge tar ea The visibdleteect-orsr cnoulad bge oeft he Complememtale onxidte/saemirconyduc - tor (CMOS) active-poei-s(AaPnS)s otyrpe . The infrared detectors could be of the ther- mopile or bolometer type CMOS readout Crouiry would be used for both sensors. The number of infrared powis need not equa the number of visible pixels The mersofp infrearedr ansd viosiblne po is Could be in any of a variety of patterns. arco ud ttehrro@u sgilehic on-b ased siindfer-abrye-ds-i daen ds uVriismiabglees- iomarge e isSee innstoerrssp ewrosueld do bres utpeegrriamtpeods edP ixielnt dheete scatomres iCmoaugled baere arar anged in