J. J. Hamilton

University of Surrey, Guildford, ENG, United Kingdom

Are you J. J. Hamilton?

Claim your profile

Publications (14)17.37 Total impact

  • ION IMPLANTATION TECHNOLOGY 2008; 11/2008
  • [Show abstract] [Hide abstract]
    ABSTRACT: The International Roadmap for Semiconductors requires ultrashallow, highly activated, abrupt dopant profiles in the source/drain extension regions, for technology nodes beyond 45 nm. The authors contrast B and BF2 implants in Si and silicon on insulator (SOI) substrates with and without a preamorphizing implant (PAI). The objective of the study is to compare between Si and SOI substrates, PAI and non-PAI condition, and B and BF2 implants. The results show the absence of the “reverse annealing effect” in BF2 implants, which is observed in B implants. The presence of F appears to impede the formation of boron interstitial clusters, which is shown in the case of B implant. The BF2 implants follow a similar trend for SOI and Si with and without PAI.
    Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society 01/2008; 26(1):347-350. · 1.36 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The redistribution during annealing of low-energy B implants in SOI structures and in bulk Si have been investigated by comparing Secondary Ion Mass Spectrometry (SIMS) and simulated profiles. Samples preamorphised with Ge at different implantation energies have been prepared in order to investigate the effects of the damage position on B diffusion. The specimens have been subsequently B implanted at 500 eV with doses 2times10<sup>13</sup> and 2times10<sup>14</sup> cm<sup>-2</sup> and annealed between 700 and 1100degC. SIMS profiles show a B pile-up in the first few nanometres of the Si matrix on the Si surface. Simulations of diffused profiles indicate that the B redistribution upon annealing can be explained by assuming that the mobility of the dopant which arrives in proximity of the surface is practically annulled. The amount of B trapped at the surface is maximum at the temperatures around 800degC, when more than 80% of the implanted dopant is made immobile and electrically inactive. The trapped B increases with reducing the depth of the amorphous layer and it is higher in the bulk Si than in SOI. By comparing Hall measurements and the amount of B not trapped at the surface, we also estimate the amount of B that aggregates inside the Si lattice in form of clusters (BICs). For the B dose of 2times10<sup>14</sup> cm<sup>-3</sup>, after isochronal annealing of 60 s, the amount of BICs is about 3-4times10<sup>13</sup> cm<sup>-2</sup> at the lowest temperatures and tends to vanish at high temperatures.
    Advanced Thermal Processing of Semiconductors, 2007. RTP 2007. 15th International Conference on; 11/2007
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Redistribution during annealing of low-energy boron (B) implants in silicon on insulator (SOI) structures and in bulk Si has been investigated by comparing secondary ion mass spectrometry (SIMS) and simulated profiles. All the samples have been preamorphized with Ge at different implantation energies in order to investigate the effects of the position of the damage on B diffusion. Different B doses in the range between 2x10(13) and 2x10(15) cm(-2) and annealing temperatures between 700 and 1100 degrees C have been investigated. All SIMS profiles show a B pileup in the first few nanometers of the Si matrix in proximity of the Si surface. The results of our simulations, performed on samples implanted at different doses (below and above the solid solubility), indicate that the B redistribution upon annealing can be explained with a simple model which considers the presence of traps in the surface region, without considering any asymmetric behavior of the dopant diffusion. The sink region is a few monolayers (1-2 nm) for doses of 2x10(13) and 2x10(14) cm(-2), and it extends to about 7 nm for the highest dose of 2x10(15) cm(-3), in the region of very high B concentration where precipitates and clusters shrink the incoming B atoms. For the two lowest B doses, the amount of B trapped at the surface is maximum at temperatures around 800 degrees C, when more than 80% of the implanted dopant is made immobile and electrically inactive. In our experimental conditions, i.e., preamorphization performed with constant dose and different implantation energies, the amount of trapped B increases with reducing the depth of the amorphous layer and it is higher in the bulk Si than in SOI.
    Journal of Applied Physics 01/2007; · 2.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Preamorphization of ultrashallow implanted boron in silicon on insulator is optimized to produce an abrupt boxlike doping profile with negligible electrical deactivation and significantly reduced transient enhanced diffusion. The effect is achieved by positioning the as-implanted amorphous/ crystalline interface close to the buried oxide interface to minimize interstitials while leaving a single-crystal seed to support solid-phase epitaxy. Results support the idea that the interface between the Si overlayer and the buried oxide is an efficient interstitial sink.
    Applied Physics Letters 01/2007; 91(9):092122. · 3.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Preamorphising implants (PAI) in Silicon-on-insulator (SOI) compared with bulk silicon substrates have been shown to improve junction properties. This paper studies the optimization of electrical behavior of this process in SOI. We will show that the deactivation caused by end-of-range (EOR) defects is vastly reduced in SOI by positioning the EOR band as close as possible to the buried oxide (BOX) interface while still allowing crystal regrowth to occur. Results show a 3% deactivation in SOI compared to 10% in bulk Si.
    01/2006;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The fabrication of preamorphized p-type ultrashallow junctions in silicon-on-insulator 􏰹SOI􏰸 has been investigated. Electrical and structural measurements after annealing show that boron deactivation and transient enhanced diffusion are reduced in SOI compared to bulk wafers. The reduction is strongest when the end-of-range defects of the preamorphizing implant are located deep within the silicon overlayer of the SOI silicon substrate. Results reveal a very substantial increase in the dissolution rate of the end-of-range defect band. A key player in this effect is the buried Si/SiO2 interface, which acts as an efficient sink for interstitials competing with the silicon surface.
    Applied Physics Letters 01/2006; 89:042111. · 3.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: P-type ultrashallow junctions are widely fabricated using Ge preamorphization prior to ultralow-energy boron implantation. However, for future technology nodes, issues arise when bulk silicon is supplanted by silicon-on-insulator (SOI). An understanding of the effect of the buried Si/SiO2 interface on defect evolution, electrical activation, and diffusion is needed in order to optimize the preamorphization technique. In the present study, boron has been implanted in germanium preamorphized silicon and SOI wafers with different preamorphizing implant conditions. Subsequent to implantation an isothermal annealing study of the samples was carried out. Electrical and structural properties were measured by Hall-effect and secondary-ion-mass spectroscopy techniques. The results show a variety of interesting effects. For the case where the Ge preamorphization end-of-range defects are close to the buried oxide interface, there is less dopant deactivation and less transient-enhanced diffusion, due to a lower interstitial gradient towards the surface.
    Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society 01/2006; 24(1). · 1.36 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Preamorphization implant (PAI) prior to dopant implantation, followed by solid phase epitaxial regrowth (SPER) is of great interest due to its ability to form highly-activated ultra- shallow junctions. Coupled with growing interest in the use of silicon-on-insulator (SOI) wafers, modeling and simulating the influence of SOI structure on damage evolution and ultra-shallow junction formation is required. In this work, we use a kinetic Monte Carlo (kMC) simulator to model the different mechanisms involved in the process of ultra-shallow junction formation, including amorphization, recrystallization, defect interaction and evolution, as well as dopant- defect interaction in both bulk silicon and SOI. Simulation results of dopant concentration profiles and dopant activation are in good agreement with experimental data and can provide important insight for optimizing the process in bulk silicon and SOI.
    MRS Online Proceeding Library 01/2006; 912:99.
  • [Show abstract] [Hide abstract]
    ABSTRACT: For CMOS technology, generations beyond the 65nm node a major goal is achieving highly activated, ultra-shallow and abrupt profiles. In the case of p-type (boron) implants, one method to achieve this is using Ge preamorphization (PAI) prior to ultra-low energy B implantation. However, for future technology nodes, new issues arise when bulk silicon is supplanted by silicon-on-insulator (SOI). Understanding the strong impact of the buried Si/SiO2 interface, will enable tests of fundamental models on defect evolution, electrical activation and diffusion. In the present study, boron has been implanted in germanium-preamorphized silicon and SOI wafers. Subsequent to implantation, an isochronal and isothermal annealing study of the samples was carried out. Electrical and structural properties were measured by Hall effect and SIMS techniques. The results show a range of effects in both substrate types, including TED and deactivation driven by interstitials from the end-of-range (EOR) defects. However, in the SOI material there is a lower boron deactivation and the EOR defects are eliminated at a lower thermal budget in SOI than in the bulk silicon due to competition between the upper SOI interface and the Si surface which both act as sinks for interstitials.
    Materials Science and Engineering B 12/2005; 124:215-218. · 1.85 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: First results on the effects of strain on transient enhanced diffusion and deactivation of As-implanted ultrashallow junctions are presented. A significant effect of strain on the magnitude and timescale of transient enhanced diffusion is observed, which is consistent with the stabilization of interstitial-type defects by tensile strain. Our results show no significant impact of strain on As electrical activity during the deactivation timescale accessed in this study.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 01/2005; · 1.19 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The formation of highly activated ultra-shallow junctions (USJ) is one of the key requirements for the next generation of CMOS devices. One promising method for achieving this is the use of Ge preamorphising implants (PAI) prior to ultra-low energy B implantation. In future technology nodes, bulk silicon wafers may be supplanted by Silicon-on-Insulator (SOI), and an understanding of the Solid Phase Epitaxial (SPE) regrowth process and its correlation to dopant electrical activation in both bulk silicon and SOI is essential in order to understand the impact of this potential technology change. This kind of understanding will also enable tests of fundamental models for defect evolution and point-defect reactions at silicon/oxide interfaces. In the present work, B is implanted into Ge PAI silicon and SOI wafers with different PAI conditions and B doses, and resulting samples are annealed at various temperatures and times. Glancing-exit Rutherford Backscattering Spectrometry (RBS) is used to monitor the regrowth of the amorphous silicon, and the resulting redistribution and electrical activity of B are monitored by SIMS and Hall measurements. The results confirm the expected enhancement of regrowth velocity by B doping, and show that this velocity is otherwise independent of the substrate type and the Ge implant distribution within the amorphised layer. Hall measurements on isochronally annealed samples show that B deactivates less in SOI material than in bulk silicon, in cases where the Ge PAI end-of-range defects are close to the SOI back interface.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 01/2005; 237:107-112. · 1.19 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The work carried out here examines the suitability of BBr2+ and B+ + Br+ implants into crystalline (1 0 0) silicon for ultra-shallow junctions (USJ) applications. Rutherford backscattering spectroscopy (RBS) shows that an amorphous region is created during implantation of BBr2+, eliminating the need for a separate pre-amorphising implant. This amorphous region re-grows during subsequent rapid thermal annealing and there is evidence that bromine retards the re-growth velocity. Hall Effect measurements after rapid thermal annealing show a difference in electrical activation between the BBr2+ and B+ + Br+ implants with the latter having the lower activation. Anomalous Hall mobility is also observed for the molecular implant at lower annealing temperatures.
    Materials Science and Engineering: B. 01/2005; s 124–125:196–199.
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper investigates the electrical activation of boron halide molecular implants into silicon and compares them to boron implants at the same effective energy. The implanted species: B+, BF2+, BCl2+ and BBr2+ were implanted to doses of 2×1014 and 1×1015Bcm−2 the energy of the molecular implants was calculated to give an effective boron implant energy of 5keV. Samples cut from the wafers were annealed for 30s at temperatures ranging from 800°C to 1100°C. Hall effect measurements were used to compare and contrast the electrical activation of the boron between the different halide species and doses. It was found that molecular implants of BBr2+ and BCl2+ do not enhance the electrical activation of boron to the same extent that BF2+ implants do. The BBr2+ implants are only comparable with boron after annealing at high temperatures (above 1000°C). The BF2+ implants show enhanced electrical activation with respect to boron for all the annealing temperatures and doses studied.Rutherford backscattering spectroscopy (RBS) of silicon implanted with BBr2+ to a dose of 1×1015boron atomscm−2, shows that an amorphous region is created during the implantation. This region fully re-grows after annealing at 1100°C; lower temperature anneals remove only part of the amorphous layer. RBS channelling shows that a fraction of the bromine takes up substitutional lattice sites upon implantation, and that this fraction increases as the samples are annealed at temperatures above 600°C with 40% of the B being in substitutional sites after annealing at 1050°C.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 01/2005; 237(1):93-97. · 1.19 Impact Factor