@article{srinivasan_parsons_1998, title={Hydrogen abstraction kinetics and crystallization in low temperature plasma deposition of silicon}, volume={72}, ISSN={["0003-6951"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000071619600022&KeyUID=WOS:000071619600022}, DOI={10.1063/1.120785}, abstractNote={Exposing a plasma deposited hydrogenated silicon layer to atomic hydrogen results in hydrogen removal from the silicon/hydrogen surface and a net reduction in the total hydrogen content in the layer. For deposition at low temperature, the crystallization fraction corresponds directly with the extent of hydrogen removal. Silicon films deposited using alternating deposition and hydrogen (or deuterium) plasma exposure are characterized by transmission infrared spectroscopy and Raman spectroscopy. Using mass spectroscopy, hydrogen abstraction and etching are observed and identified as important pathways for hydrogen removal at substrate temperatures between 25 °C and 300 °C. Moreover, the hydrogen abstraction kinetics show that the reaction is first order with an activation barrier of −0.4±1 kcal/mol, consistent with a spontaneous Eley–Rideal abstraction process. Energy barrier values are supported by ab initio calculations.}, number={4}, journal={APPLIED PHYSICS LETTERS}, author={Srinivasan, E and Parsons, GN}, year={1998}, month={Jan}, pages={456–458} }
 @article{smith_read_yang_srinivasan_courtney_lamb_parsons_1998, title={Plasma enhanced selective area microcrystalline silicon deposition on hydrogenated amorphous silicon: Surface modification for controlled nucleation}, volume={16}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000074150400079&KeyUID=WOS:000074150400079}, DOI={10.1116/1.581144}, abstractNote={Selective deposition of μc-Si on hydrogenated amorphous silicon is demonstrated using time-modulated silane reactant flow in a low temperature plasma enhanced process. Alternating cycles of thin silicon layer deposition and atomic hydrogen exposure result in silicon layers on receptive surfaces, with no net deposition on nonreceptive areas of the substrate. Selective deposition could be useful to form self-aligned contacts in hydrogenated amorphous silicon (a-Si:H transistor applications. However, a problem commonly observed in low temperature selective deposition is that the selective process tends to etch amorphous silicon, harming the devices. We describe a technique involving Mo metallization that stabilizes the a-Si:H surface with respect to hydrogen plasma exposure and allows selective μc-Si deposition on a-Si:H in device structures, while avoiding deposition on the top SiNx insulator material. Surfaces and subsequent selective nucleation and growth were characterized using atomic force microscopy, x-ray photoelectron spectroscopy, and Auger electron spectroscopy, which revealed the presence of Mo incorporation in the a-Si:H surface remaining after complete removal of the metal layer. A direct comparison of selective deposition experiments on films prepared with and without Mo treatment demonstrate that the metallization stabilizes nucleation of microcrystalline silicon on amorphous silicon surfaces.}, number={3}, journal={Journal of Vacuum Science & Technology a-Vacuum Surfaces and Films}, author={Smith, LL and Read, WW and Yang, CS and Srinivasan, E and Courtney, CH and Lamb, HH and Parsons, Gregory}, year={1998}, pages={1316–1320} }
 @article{yang_read_arthur_srinivasan_parsons_1998, title={Self-aligned gate and source drain contacts in inverted-staggered a-Si : H thin-film transistors fabricated using selective area silicon PECVD}, volume={19}, ISSN={["0741-3106"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000073727100002&KeyUID=WOS:000073727100002}, DOI={10.1109/55.678536}, abstractNote={This article demonstrates full self-aligned inverted-staggered amorphous silicon thin-film transistors (TFT's) fabricated using selective plasma deposition of doped microcrystalline silicon source/drain contacts. Back-side exposure, using the bottom metal gate as the mask, produced the self-aligned contact openings. Selective deposition of the n+ silicon contact layer assures self-aligned ion resistance contacts and eliminates the need for reactive ion etching of the n+ silicon. Complete TFT fabrication requires no critical alignment steps. Transistors have linear mobility between 0.6 and 1.1 cm/sup 2//Vs, threshold voltage of 3.0 V, and sub-threshold slope of 0.35 V/decade. The OFF current is <10/sup -11/ A with -10 V gate voltage and 10 V between the source and drain, and ON/OFF ratios exceed 10.}, number={6}, journal={IEEE ELECTRON DEVICE LETTERS}, author={Yang, CS and Read, WW and Arthur, C and Srinivasan, E and Parsons, GN}, year={1998}, month={Jun}, pages={180–182} }
 @article{srinivasan_lloyd_parsons_1997, title={Dominant monohydride bonding in hydrogenated amorphous silicon thin films formed by plasma enhanced chemical vapor deposition at room temperature}, volume={15}, ISSN={["0734-2101"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:A1997WD69000015&KeyUID=WOS:A1997WD69000015}, DOI={10.1116/1.580480}, abstractNote={Hydrogenated amorphous silicon (a-Si:H) prepared by plasma enhanced chemical vapor deposition (PECVD) with silane, typically shows significant dihydride bonding and high defect density when the substrate temperature is less than 200 °C. Monohydride bonding is associated with low defect densities, and is usually observed only above 250 °C. Using rf (13.56 MHz) PECVD, we have deposited a-Si:H films at a substrate temperature of 35 °C using silane diluted with helium, and found that films with dominant monohydride bonding can be deposited without significant substrate heating. A specific ion enhanced reaction mechanism that is consistent with the results is proposed. As deposited, the films with predominant monohydride bonding show low dark conductivity (10−9 S/cm) and low photoconductivity (10−7 S/cm under 100 mW/cm2 while light illumination). Annealing the films for 3–4 h at 150 °C, resulted in an improved photoconductivity with photo to dark conductivity ratio near 105. These films may be valuable for the fabrication of thin film electronics on novel substrates compatible with only low temperature processes.}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS}, author={Srinivasan, E and Lloyd, DA and Parsons, GN}, year={1997}, pages={77–84} }
 @article{srinivasan_parsons_1997, title={Hydrogen elimination and phase transitions in pulsed-gas plasma deposition of amorphous and microcrystalline silicon}, volume={81}, ISSN={["0021-8979"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:A1997WP16700065&KeyUID=WOS:A1997WP16700065}, DOI={10.1063/1.364309}, abstractNote={Removal of hydrogen from the growth surface during silane plasma deposition of silicon is correlated with the transition from amorphous to microcrystalline film structure. Plasma deposition experiments were performed using a pulsed gas technique, where repeated steps of thin amorphous silicon film deposition, and atomic hydrogen (or deuterium) exposure are used to form microcrystalline and polycrystalline thin films at substrate temperatures below 250 °C. Infrared absorption and Raman spectroscopy are used to estimate the silicon-hydrogen bonding concentrations, and characterize crystal structure, respectively. Hydrogen elimination probed using real-time differentially pumped mass spectroscopy demonstrates that during atomic deuterium exposure, hydrogen abstraction by deuterium, rather than silicon etching, is the primary mechanism for hydrogen removal from the depositing surface. Polycrystalline material, with no shoulder at 480 cm−1 in the Raman spectrum, and grain sizes greater than 1000 Å, as determined by transmission electron microscopy, have been formed at temperatures below 250 °C. The amorphous to crystal transition is observed at substrate temperatures as low as 25 °C, with longer hydrogen exposure required at lower temperatures. Hydrogen is shown to be preferentially abstracted from monohydride (Si–H) units as compared to dihydride (SiH2) units at or near the depositing growth surface, consistent with ab initio energy calculations of hydrogen interactions with silicon hydrides. A transition in hydrogen removal kinetics is observed upon film crystallization, where the rate of hydrogen removal is reduced for more crystalline materials. These results are valuable for understanding surface reactions in low temperature crystalline silicon deposition, for example, for fabrication of high mobility thin film transistor structures on glass.}, number={6}, journal={JOURNAL OF APPLIED PHYSICS}, author={Srinivasan, E and Parsons, GN}, year={1997}, month={Mar}, pages={2847–2855} }
 @article{smith_srinivasan_parsons_1997, title={Investigation of substrate dependent nucleation of plasma-deposited microcrystalline silicon on glass and silicon substrates using atomic force microscopy}, volume={82}, ISSN={["0021-8979"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000071043400022&KeyUID=WOS:000071043400022}, DOI={10.1063/1.366471}, abstractNote={In order to define mechanisms for pulsed-gas plasma enhanced substrate-selective deposition of silicon, the initial stages of microcrystalline silicon (μc-Si) growth by plasma enhanced chemical vapor deposition on both c-Si and glass substrates were investigated by means of atomic force microscopy (AFM) and reflective high energy electron diffraction (RHEED). Differences in initial substrate morphology were reflected in significant differences in film surface morphology in the early stages of growth. AFM images and rms roughness measurements indicated that the initial growth on the c-Si substrate was three dimensional in character. On glass, the initial Si deposits were much more irregular in shape and the tallest features extended over wider areas than the initial deposits on c-Si. The character of the initial growth on glass was partly obscured by the roughness of the substrate, but the appearance of the initial Si deposits suggested a flatter and more two-dimensional character on glass than on c-Si. As the Si deposition progressed, the films on the different substrates developed similar morphology with increasing thickness. On the c-Si substrate, surface coverage was nearly complete at 50 Å. RHEED analysis of the films grown on c-Si revealed the presence of amorphous structure in the early stages of film growth, which began to transition to a randomly oriented μc-Si structure after 40–50 Å of growth. Observed differences in nucleation affirm and clarify proposed mechanisms and limitations for plasma enhanced selective μc-Si deposition.}, number={12}, journal={JOURNAL OF APPLIED PHYSICS}, author={Smith, LL and Srinivasan, E and Parsons, GN}, year={1997}, month={Dec}, pages={6041–6046} }