Varian Semiconductor Equipment Associates

Gloucester, MA, United States

Varian Semiconductor Equipment Associates

Gloucester, MA, United States
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Stojanovic V.D.,University of Belgrade | Raspopovic Z.M.,University of Belgrade | Jovanovic J.V.,University of Belgrade | Radovanov S.B.,Varian Semiconductor Equipment Associates | And 2 more authors.
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2012

Boron produced in plasma devices continues to be the main p-type dopant in ion implantation of semiconductor devices. Yet plasma parameters of most frequently used Boron rich gas, BF 3, are not well established. Time resolved measurements of ion energy distributions in the cathode boundary [1] of a pulsed dc plasma doping system revealed possible role of the charge-transfer collisions between singly charged ions of various mass. The cross sections for scattering of B +, BF + and BF2+ ions on BF 3 molecule are calculated by using Nanbu's theory [2] separating elastic from reactive collisions. A Monte Carlo simulation technique was applied to perform calculations of transport parameters in DC electric fields. © 2011 Elsevier B.V. All rights reserved.


Darby B.L.,University of Florida | Yates B.R.,University of Florida | Rudawski N.G.,University of Florida | Jones K.S.,University of Florida | And 2 more authors.
Thin Solid Films | Year: 2011

The formation of voids in ion-implanted Ge was studied as a function of ion implantation energy and dose. (001) Ge substrates were self-implanted at energies of 20-300 keV to doses of 1.0 × 10 13-1.0 × 10 17 cm - 2. Transmission electron microscopy revealed clusters of voids just below the surface for implant energies ≤ 120 keV at a dose of 2.0 × 10 15 cm - 2 and complete surface coverage for an implant energy of 130 keV and doses ≥ 1.0 × 10 16 cm - 2. Void clusters did not change in size or density after isothermal annealing at 330 °C for 176 min. The initial void formation is discussed in terms of the vacancy clustering and "microexplosion" theories with a damage map detailing the implant conditions necessary to produce voids. © 2011 Elsevier B.V. All rights reserved.


Darby B.L.,University of Florida | Yates B.R.,University of Florida | Rudawski N.G.,University of Florida | Jones K.S.,University of Florida | Kontos A.,Varian Semiconductor Equipment Associates
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2011

The effects of implantation energy and dose on Ge solid-phase epitaxial growth kinetics were studied using (0 0 1) Ge substrates self-implanted at energies of 20-150 keV and doses of 1 × 1014-2 × 10 15 cm-2. All implants produced a continuous amorphous layer, which was crystallized by annealing at 330 °C for 22-176 min. At lower doses, the growth velocity was implant energy-independent while at higher doses the growth rate tended to decrease with decreasing implant energy. The decrease in growth velocity with energy at higher doses is discussed in terms of possible implantation-induced stresses altering growth kinetics. © 2010 Elsevier B.V. All rights reserved.


Renau A.,Varian Semiconductor Equipment Associates
IWJT-2010: Extended Abstracts - 2010 International Workshop on Junction Technology | Year: 2010

Recent innovations in ion implantation technology that overcome scaling barriers at 32nm/22nm are reviewed. Some of the hardware improvements will be discussed, but the main focus will be on the process and device data that demonstrates their advantages. These innovations include a cryogenic implant capability that enables a significant reduction in implantation induced crystal damage, molecular implants that show device performance improvements and that use standard ion sources, and various approaches that improve implant performance, particularly when diffusion-less anneal is used. © 2010 IEEE.


Renau A.,Varian Semiconductor Equipment Associates
Review of Scientific Instruments | Year: 2010

For many years the largest commercial application for particle accelerators has been semiconductor ion implantation. These tools differ from other accelerators in many respects. In particular they are automated to a very high degree and, in addition to technical performance requirements their success depends on other key metrics including productivity, availability and cost of ownership. These tools also operate with a large variety of species, four orders of magnitude of energy range and five orders of magnitude of dose range. The ion source is a key component of implanters with its own performance metrics that include beam current, lifetime, and materials cost. In this paper, we describe the primary applications for ion implantation and some of the beam line architectures that are used. We describe the ion source that has evolved for this application. Some key future challenges for implanter ion source development are also discussed. © 2010 American Institute of Physics.


Renau A.,Varian Semiconductor Equipment Associates
ECS Transactions | Year: 2011

The last few years have seen significant developments in ion implantation: Commercial implanters are now available with cryogenic capabilities to enable significant reductions in implant induced crystal damage; Plasma doping tools are now extensively used in fabs; Modified sources and new chemistries have been developed that allow some implants to be replaced by more exotic molecular implants to enable simultaneous co-implants and minimize end of range damage; Today's implanters give better dopant placement performance than ever before. These changes have been driven by CMOS scaling challenges, particularly at 32nm and 22nm, along with changes in thermal processing and the emergence of new implant applications. Details of some of these developments are given along with some explanation of the changes that have made them necessary. ©The Electrochemical Society.


Dube C.E.,Varian Semiconductor Equipment Associates | Tsefrekas B.,Varian Semiconductor Equipment Associates | Buzby D.,Heraeus Holding GmbH | Tavares R.,Heraeus Holding GmbH | And 5 more authors.
Energy Procedia | Year: 2011

In this paper we present recent advances of the Varian patterned ion implantation selective emitter solar cell process, Solion Blue. Varian's ion implantation system, known as Solion, is currently deployed in manufacturing. This novel doping approach enables 1) simplification of the process flow by eliminating the non-value add steps such as PSG etch and junction isolation common to diffusion-based processes, 2) improved junction quality compared to diffusion processes through precise dopant control, and 3) improved surface passivation using a thermal oxide/silicon nitride ARC. Improvements in emitter quality, through oxide passivation and elimination of the "dead" layer associated with diffusion based processes, has enabled production of >18.5% efficiency solar cells with simplified processing. The Solion Blue process enables patterned doping using in situ masking, rendering manufacturing of a precise selective emitter with an additional cell efficiency boost. Here we report on the first in a series of optimizations of the ion implanted selective emitter cell process, focusing on assessing the impact of the metallization contact width. These results suggest that, unlike diffusion based selective emitter processes, in which the focus is minimization of the contact width, due to attendant higher surface recombination, the ion implant selective emitter architecture is relatively invariant with contact width, thus enabling a wider contact window. Good surface passivation, precision doping and simplified processing make a compelling case for patterned ion implantation as the preferred doping approach for selective emitter cells and other high efficiency cell architectures, including those that require patterned boron. © 2010 Published by Elsevier Ltd.


Walther T.,University of Sheffield | England J.,Varian Semiconductor Equipment Associates
Journal of Physics: Conference Series | Year: 2011

High-resolution electron microscopy (HREM), chemical mapping by energy-filtered transmission electron microscopy (EFTEM), electron energy-loss spectroscopy (EELS) and energy-loss spectroscopic profiling (ELSP), also called spectroscopic transverse image profiling by EFTEM (stripeTEM) have been combined to study the distribution of boron after implantation into silicon at low energy (0.5keV) and rapid thermal annealing. The key to the experiments is that stripeTEM combines both ∼1nm spatial resolution and sub-at% sensitivity. It is shown that the near-surface spike of boron visible in secondary ion mass spectrometry (SIMS) profiles is an artefact of surface profiling. The real distribution of boron is several nm deeper into the specimen, in agreement with both Monte Carlo simulations and shoulders apparent in the SIMS profile. Quantification of the experimental stripeTEM data shows that the B concentration is approximately ∼2at% in the SiO2 and ∼4at% in the Si, with statistical errors of about ±0.2at% due to noise and background fitting and systematic errors of ±0.6at% due to uncertainties in the scattering cross-sections.


Kawski J.L.,Varian Semiconductor Equipment Associates
Solid State Technology | Year: 2011

Certain inherent process characteristics such as precision, cleanliness, control and high productivity have been the hallmark of the entire implant industry for some time. Coupled with new capability, implant has become less of a commodity product and more enabling. In fact, the makers of the industry's next-generation devices are looking to implant to improve established doping applications and facilitate new precision materials modification applications to provide device performance and yield improvements required for 22nm.


Patent
Varian Semiconductor Equipment Associates | Date: 2010-04-15

A plasma processing method is provided. The plasma processing method includes using the after-glow of a pulsed power plasma to perform conformal processing. During the afterglow, the equipotential field lines follow the contour of the workpiece surface, allowing ions to be introduced in a variety of incident angles, especially to non-planar surfaces. In another aspect of the disclosure, the platen may be biased positively during the plasma afterglow to attract negative ions toward the workpiece. Various conformal processing steps, such as implantation, etching and deposition may be performed.

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