Bulletin of the American Physical Society
62nd Annual Gaseous Electronics Conference
Volume 54, Number 12
Tuesday–Friday, October 20–23, 2009; Saratoga Springs, New York
Session GT1: Plasma Aided Implantation |
Hide Abstracts |
Chair: Svetlana Radovanov, Varian Semiconductor Room: Saratoga Hilton Ballroom 1 |
Tuesday, October 20, 2009 10:00AM - 10:30AM |
GT1.00001: Sheath dynamics and energetic particle distributions on substrates Invited Speaker: The energy and angular distributions (EAD's) of energetic particles arriving at a substrate determine crucial plasma processing characteristics; thus knowledge and control of the EAD's are vital for nanoelectronics design and fabrication during scale-down to the ultimate 4--6 nm transistor gate lengths over the next 15 years. We review the history and state-of-the-art of measurements, simulations, and analyses of ion, fast neutral, and ballistic electron EAD's. Ion measurements have been made using electrostatic energy analyzers, cylindrical mirror analyzers, and retarding grid analyzers, often now coupled with quadrupole mass spectrometers to compare different ions in the same discharge. The state-of-the-art for capacitive rf sheaths has advanced greatly since the first observation of a bi-modal ion energy distribution (IED) over 50 years ago. More recently, measurement techniques and models have been developed to determine fast neutral distributions. Monte Carlo, and particle-in-cell simulations with Monte Carlo collisions (PIC-MCC) have been used to study IED's since the late 1980's. Recently, PIC-MCC simulations were used to obtain ballistic electron EAD's. Analytical models of the IED for collisionless rf sheaths have emphasized the role of $\tau_i/\tau_{rf}$, the ratio of ion transit time across the sheath to rf period, with separate models for the low and high frequency regimes. Various simplifications and bridging models now exist. For collisional rf sheaths, the important role of $\lambda_i/s$, the ratio of ion-neutral mean free path to sheath width, in modifying the collisionless bi-modal IED was demonstrated in the early 1990's. Surface charging effects on insulating substrates are important for low frequency rf discharges or for pulsed transient sheaths; the latter are found during plasma ion implantation processes. Analytical models of the IED for plasma ion implantation have been extended to insulating surfaces and compared with experimental results. [Preview Abstract] |
Tuesday, October 20, 2009 10:30AM - 11:00AM |
GT1.00002: Multi-frequency, finite-wavelength and dc-augmentation effects in large area capacitive sources Invited Speaker: The scaling of high frequency, multi-frequency capacitively coupled plasmas (CCPs) to large areas has many challenges. It has been well established that electromagnetic (EM) effects become increasingly more important as the frequency of excitation increases while the diameter of the substrate also increases. The complexity of the system increases with the addition of dc-augmentation. Although much as been learned about EM effects, scaling laws are difficult to develop because the discharge characteristics are functions of the frequency dependence of the conductivity, the response of the electron energy distribution (EED) to the electric fields that penetrate into the plasma, the geometry of the reactor, gas mixture, pressure and dc augmentation power. In the case of multi-frequency excitation, the coupling of low and high frequencies through surface waves and through the bulk plasma is also an issue. In this talk we will discuss results from a computational investigation of multi- and high- frequency (up to 200 MHz) excitation of CCPs having diameters up to 450 mm, with and without dc augmentation. The model used in this study includes a full time-domain solution of Maxwell's equations that enables investigation of coupling between frequencies. A Monte Carlo simulation is used to predict EEDs as a function of position and ion energy distributions to the substrate. Gas mixtures (e.g., Ar and Ar/CF$_{4})$, pressures (10 mTorr to 100 mTorr) and geometry (gap size) are investigated. Methods to minimize EM effects will be discussed by using variable conductivity and shaped electrodes; and segmented electrodes in which the electrical path from the generator to any point in the plasma is made as consistent as possible. [Preview Abstract] |
Tuesday, October 20, 2009 11:00AM - 11:15AM |
GT1.00003: Self-Regulation Plasma Doping for 2D and 3D devices Bunji Mizuno Plasma Doping has been industrialized for DRAM application. On the other hand, for 3D application, conformal and shallow doping for tri-gate and side-wall doping for fins are required to form junctions on the side-walls. This requirement is quite difficult to be realized by conventional ion implantation (\textbf{II}) or cluster \textbf{II}. Plasma doping (\textbf{PD}) has been proposed as a candidate for this requirement. Relatively better conformality was achieved such as the ratio of the top to the side resistivity of fin is 1.4 by \textbf{PD} and 1.08 by \textbf{VPD} or \textbf{ALD}. In addition, sputter erosion for fins was the most significant issue in case of \textbf{PD}. We have been proposed \textbf{SRPD} as a technique to solve the less conformality of \textbf{II} and the less controllability of conventional \textbf{PD}, \textbf{VPD} and \textbf{ALD}. We present New Self-Regulation Plasma Doping (n\textbf{SRPD}) with B$_{2}$H$_{6}$/He plasma that has been developed to provide precisely controllable ultra-shallow junctions for planar FET and conformal junctions for 3D structures. Manufacturing level of process controllability ($<$1{\%} on dose) and advantage on the devices of n\textbf{SRPD} has been achieved with FinFETs and planar pMOSFETs. This n\textbf{SRPD} has been developed on commercially available and production worthy plasma platform. [Preview Abstract] |
Tuesday, October 20, 2009 11:15AM - 11:30AM |
GT1.00004: Advanced Dopant Profile Control for Plasma Doping Processes Ludovic Godet, Shu Qin, Ziwei Fang, G.D. Papasouliotis, Timothy Miller, Vikram Singh, Svetlana Radovanov After intense research and development of plasma doping systems, successful application in low energy ion implantation has been demonstrated. Plasma doping enables new fabrication options for advanced CMOS and non-planar devices. Understanding plasma-surface interactions during plasma implantation is critical for successful development of new applications. During plasma immersion ion implantation, ionized species present in the plasma are extracted and implanted into the wafer, and, in addition, many other physical mechanisms, such as deposition, etching and sputtering, are competing in parallel. The dopant profile into the substrate results from contributions of all these mechanisms. By optimizing plasma composition and balancing deposition, etching and sputtering of the implanted surface, the dopant profile can be modified from typical surface peaked to retrograde/Gaussian profile. In this study, we report on the dopant profile optimization using ion mass spectrometry. [Preview Abstract] |
Tuesday, October 20, 2009 11:30AM - 11:45AM |
GT1.00005: One-Step, Non-Contact Pattern Transfer by Direct-Current Plasma Immersion Ion Implantation Dixon T.K. Kwok, Paul K. Chu A one-step non-contact pattern transferring method is demonstrated. Clear non-identical images with well-defined boundaries are simultaneously transferred to a substrate by -15 kV plasma immersion ion implantation through a patterned metal mask. The metal mask is 6 cm away from the substrate and no lens system is necessary for the pattern transfer. To avoid diversification of compensating ions, the electric field must be smoothed out by the fine mesh overlapping on top of the metal mask. Complex patterns with micrometer size line-widths can be transferred onto a silicon wafer by placing the metal masks 4 mm away from the wafer. Scanning electron microscopy (SEM) discloses that by negatively biasing the metal mask, ions coming from a hole with a diameter of 200 micrometers in the mask can be confined to a smaller region of 100 micrometers. The ion focusing effect is confirmed by two-dimensional multiple grid particle-in-cell (PIC) simulation. [Preview Abstract] |
Tuesday, October 20, 2009 11:45AM - 12:00PM |
GT1.00006: Transport Coefficients for Electrons in BF3 Zoran Lj. Petrovic, Zeljka Nikitovic, Olivera Sasic, Zoran Raspopovic, Vladimir Stojanovic, Svetlana Radovanov We use the available cross section data [1] for electron impact on BF3 supplemented by newly calculated cross sections for total scattering, electronic excitation and ionization [2]. Monte Carlo simulation was applied to perform calculations of transport coefficients as well as rate coefficients in DC and RF electric fields. Since BF3 has a high threshold for attachment a presence of some of the F or F2 radicals would affect the properties of plasma significantly. Thus we have supplemented the cross section set by the cross section data for the two radicals and made calculations for different abundances. In addition calculations in crossed electric and magnetic (ExB) fields have been made together with calculations for time resolved coefficients (E(t)xB(t)). We discuss the differences between the original and new cross section set and try to discuss how these will affect the operation of discharges used for ion implantation. \\[4pt] [1] S. Biagi, 2005 unpublished.\\[0pt] [2] M. Vranic, J. Varhambia, M. Radmilovic, J. Tennyson, Z. Lj. Petrovic 2009 to be published. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2025 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700