@article{ban_ozturk_misra_wortman_venables_maher_1999, title={A low-thermal-budget in situ doped multilayer silicon epitaxy process for MOSFET channel engineering}, volume={146}, ISSN={["0013-4651"]}, DOI={10.1149/1.1391744}, abstractNote={This paper describes an in situ boron‐doped, multilayer epitaxial silicon process that can be used to obtain doping profiles for channels in the deep‐submicron regime. We have extensively studied lightly doped channel structures in which an intrinsic silicon layer is grown on an in situ doped epitaxial silicon film. Low‐thermal‐budget processing is achieved by the ultrahigh‐vacuum rapid thermal chemical vapor deposition technique which combines low‐temperature surface preparation and deposition (≤800°C) while providing high growth rates using disilane . Boron doping is achieved using diborane diluted in hydrogen (500 ppm) as the precursor. Temperature and gas switching are compared in terms of doping transition, interface contamination (carbon and oxygen incorporation), and impurity diffusion upon annealing. Our results reveal that for a contamination‐free epitaxial silicon interface, interfacial carbon contamination must be eliminated or reduced to a minimum level. Using this process, short‐channel n‐channel metal‐oxide semiconductor devices μm) have been fabricated for the first time demonstrating the potential use of the technique. It was found that lightly doped channel metal‐oxide semiconductor field effect transistors are more easily scalable into the 0.1 μm regime with superior short‐channel characteristics. © 1999 The Electrochemical Society. All rights reserved.}, number={3}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Ban, I and Ozturk, MC and Misra, V and Wortman, JJ and Venables, D and Maher, DM}, year={1999}, month={Mar}, pages={1189–1196} }
 @article{ban_ozturk_1999, title={In situ phosphorus doping during silicon epitaxy in an ultrahigh vacuum rapid thermal chemical vapor deposition reactor}, volume={146}, ISSN={["0013-4651"]}, DOI={10.1149/1.1392631}, abstractNote={Phosphorus incorporation during selective silicon epitaxy using the phosphine (PH 3 ), disilane (Si 2 H 6 ), and chlorine (Cl 2 ) chemistry in a cold-wall ultrahigh vacuum rapid thermal chemical vapor deposition reactor was investigated. We have studied the dependence of silicon growth rate and phosphorus incorporation on phosphine partial pressure and temperature in the range of ∼10 -9 to 10 -6 Torr, and 650 to 800°C, respectively. Even at such low partial pressures, phosphorus concentration above 10 18 cm -3 was obtained due to the high sticking coefficient of phosphine. Phosphorus incorporation was found to be a strong function of temperature. Two possible incorporation mechanisms have been discussed in detail: surface electronic effects created by silicon becoming extrinsic at high phosphorus concentrations and high phosphorus surface coverage in the form of P-P dimers. A reduction in silicon growth rate was observed due to phosphine. Doping concentration was found to be uniform in the films at low temperatures (650-750°C) accompanied with by phosphorus peaks at interfaces for growth temperatures above 800°C. A significant chamber memory effect was observed in the process which prohibits intrinsic silicon deposition following an in situ phosphorus-doped layer.}, number={11}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Ban, I and Ozturk, MC}, year={1999}, month={Nov}, pages={4303–4308} }
 @article{ban_ozturk_demirlioglu_1997, title={Suppression of oxidation-enhanced boron diffusion in silicon by carbon implantation and characterization of MOSFET's with carbon-implanted channels}, volume={44}, ISSN={["0018-9383"]}, DOI={10.1109/16.622613}, abstractNote={In NMOS transistors with boron-doped channels, Oxdation-Enhanced Diffusion (OED) is a key contributor to boron profile broadening. Starting with the arguments presented in several recent reports on the role of carbon in silicon as a sink for self-interstitials, we have explored the feasibility of using carbon in the Metal Oxide Silicon Field Effect Transistor (MOSFET) active region to retard boron diffusion during gate oxidation. A highly effective suppression of OED of boron was observed providing more than an order of magnitude reduction in boron diffusivity. MOSFETs with carbon- and boron-implanted channels have been fabricated to evaluate the impact of carbon on the electrical properties of Si. Boron diffusion, activation, and critical electrical parameters including subthreshold swing, threshold voltage, off-state leakage current, and channel mobility have been evaluated as a function of the carbon dose. While our results show that carbon can effectively suppress boron diffusion daring gate oxidation, carbon can also lead to poor boron activation and degradation in MOSFET performance when carbon dose levels above a threshold of /spl sim/10/sup 14/ cm/sup -2/ are utilized. Our results, however, indicate considerable improvement in boron activation with increases in the thermal budget. We show that if carbon implantation damage is annealed out prior to boron implantation, not only is boron activation improved, but carbon continues to serve as a sink for self-interstitials, thereby effectively suppressing OED.}, number={9}, journal={IEEE TRANSACTIONS ON ELECTRON DEVICES}, author={Ban, I and Ozturk, MC and Demirlioglu, EK}, year={1997}, month={Sep}, pages={1544–1551} }