Materials modification: doping of diamond by ion implantation

Ion implantation and diamond: some recent results on growth and doping

Diffusion of hydrogen in undoped, p-type and n-type doped diamonds

Ion-implanted structures and doped layers in diamond

Electron microscopy profiling of ion implantation damage in diamond: Dependence on fluence and annealing

: We are studying contact formation, regrowth and implantation doping of natural diamond, for future applications to the fabrication of devices from thin film CVD diamond. We are characterizing thin film diamonds of other ONR contractors, using ion beam methods. In the last year we concentrated on the regrowth of ion damaged layers of diamond and the doping of diamond by implantation with Na, Li and F. We observed that complete regrowth of C ion damage diamond occurred below a critical ion dose. Above that dose, a 'green phase' occurred, which was characterized by a golden green color and by the absence of recovery of the lattice, as measured by ion channeling. Implantation doping studies of Li, Na, and F were initiated, and show some promise for n-type doping of diamond. The diffusivity of Li in diamond was studied by neutron depth profiling. In the important area of regrowth of ion damaged diamond, we observed that a completely randomized lattice can be regrown when the damaged level is below a certain threshold value, characterized by a deposited energy equivalent to 12 Frenkel defects per cu nm, or about 7% defects. The kinetic mechanisms for regrowth under these conditions, and the influence of impurities such as F and H on the regrowth, are relevant to CVD growth. (EDC)

Synthetic diamond is one of the most promising materials for high power devices due to its extraordinary physical properties, such as high thermal conductivity (22 W/cm K, 4 times that of Cu), electric breakdown field (>10 MV/cm), and carrier mobility (m n =1000 cm 2 /V s , m p = 2000 cm 2 / V s ). Moreover, 3D architectures, i.e. lateral growth, allowed the use of vertical geometries for the design of such devices, in addition to other advantages such as higher miniaturization, distribution of the electric field and reduction of technology steps and costs. In fact, in the quest for power electronic devices sustaining ever higher reverse blocking voltages and forward currents, buried heavily boron doped (p + ) diamond layers have been shown recently [1] to reduce markedly the on‐state resistance (R on ) of pseudo‐vertical crystal diamond Schottky diodes. Such advanced designs rely on an improved control of selective 3D overgrowth of dry etched mesa and trenches [2]. Here, MPCVD diamond overgrowth on patterned‐etched diamond substrate is demonstrated to be highly selective depending on the methane concentration. This can be very useful for the design of 3D engineered semiconducting devices such as p‐n junctions. However, some growing conditions are shown to generate defects (dislocations, planar defects…). In addition, boron doping is also shown to induce the generation by a proximity strain related mechanism [3] of another type of defects. Mesa structures were fabricated by reactive‐ion etching (RIE) on masked substrates. Overgrowth was performed by microwave induced plasma chemical vapor deposition (MPCVD). A stratigraphic approach of heavily boron doped layers and undoped ones allows to follow the “history” of the growth, in the vicinity of mesa patterns [4], thanks to further cross section TEM observations. The latter identify and distinguish between extended defects generated by: (i) the boron inclusion, (ii) the strain related to the mesa‐step and (iii) the growth conditions. Defects are studied using dark field (DF) and weak beam DF (WB) in diffraction contrast modes on focused ion beam lamellas. From the invisibility criterion, and families of Burger vectors have been identified. Based on the position of this defects respect the MESA structure, their origin is identified to be: (i) edge and threading dislocations with type of Burger vector are favorably generated by the boron doping while (ii) planar defects with type of Burger vector are highly influenced by the strain accumulated in the corner of the step generated by the mask before the overgrowth. In addition, multilayer doping allows identifying the regions of different growth orientation in the mentioned stratigraphic approach. Susceptibility of dislocation generation by boron proximity effects respect to the surface growth orientation is well revealed in such growth geometrical design where several growth orientations have to coexist at the same time. Higher density of type (i) of defects where obtained in closer planes as (111). Finally, the role of the methane concentration in the generation of extended defects will be discussed.

Ion implantation in diamond has long been explored, but many challenges remain before it can be fully realized for practical applications. This difficulty originates from a fundamental problem: lattice damage induced by ion irradiation reduces the effective concentration of impurity atoms. Nevertheless, the successful realization of ion implantation doping would offer major advantages, including localized doping, process simplification, and self-alignment capability using pre-formed electrodes. This topical review provides a comprehensive overview of boron ion implantation in diamond, tracing its development from early research to the latest advancements. We first examine the foundational work and the persistent challenges that have hindered progress for decades, such as low doping efficiency. The latter part of this review focuses on our recent breakthroughs, which have been designed to systematically overcome these long-standing issues. Our findings in the heavy doping regime (10 19 cm −3 ) have achieved a record-breaking doping efficiency of up to 78% with high Hall mobility. Furthermore, in the light doping regime (10 16 cm −3 ), our detailed analysis has identified a deep donor-like defect, which is likely a boron-vacancy complex specific to ion implantation doping. These findings demonstrate that a multi-faceted approach—combining optimal implantation and annealing conditions, a protective layer, and high-quality substrates—can make ion implantation a practical method for localized diamond doping, paving the way for next-generation diamond power devices.

Ion implantation of diamond and diamond films

Diamond-based semiconductor devices offer the promise of operation at high temperatures and under extreme radiation conditions. An essential step in the drive towards operational diamond-based electronic devices is the ability to controllably and reproducibly dope the diamond. Ion implantation is the method of choice for such doping because it offers precise control of the dopant concentration and spatially selective doping is achievable using standard masking techniques. However, compared to silicon, the doping of diamond is complicated by the tendency of the diamond to relax to graphite upon thermal annealing. Furthermore, even if graphitization can be avoided, the compensation of dopants by residual defects has proved in the past to be a limiting factor in obtaining very high mobility material. In this paper, we present a scheme for the effective doping of diamond using MeV ion-implantation. For MeV ion- implantation the doped layer is deeply buried under a cap of undamaged diamond, and so the scheme includes a method using pulsed laser irradiation for making electrical contact to the buried layer. We show that a boron doped layer fabricated by the MeV implantation scheme has, after suitable annealing and removal of these compensating/trapping defects, very high mobility and low compensation ratio. In fact, its electrical properties are quite similar to those of natural boron-doped type IIb diamond.

Highly efficient impurity doping in diamond by ion implantation has been a crucial issue in the field of semiconductor fabrication for several decades. We investigated the electrical properties of heavily B-doped type IIa diamond introduced by ion implantation at room temperature with a shallow and flat impurity concentration of 3.6 × 1019 cm−3 (∼200 ppm) from the surface to ∼130 nm depth, followed by thermal annealing at 1150 and 1300 °C. The activation of the implanted acceptor B was a maximum of 80% for the sample into which B ions were implanted at room temperature followed by 1150 °C annealing. The hole concentration and Hall mobility at room temperature were realized to be higher than 1 × 1014 cm−3 and 110 cm2 V−1 s−1, respectively. We confirmed p-type conductivity and typical activation energy of acceptor B at wide temperatures from −100 to 800 °C for the prepared samples. It was consequently revealed from this study that at least room temperature B-implantation followed by above 1150 °C annealing is sufficiently effective for the electrical activation of B doped in high quality diamond.

In this study, n-type doped single crystal diamonds were successfully prepared under normal temperature and pressure conditions using laser-induced doping. 248nm pulsed laser beams with nanosecond duration were irradiated on the single crystal diamond substrate immersing in an 85% phosphoric acid solution and it introduced phosphorus doping to form an n-type doped thin layer. The resistivity of the doped region significantly decreased compared to that of the single crystal diamond. After depositing a titanium electrode, the resistivity of the doped film obtained by Van der Pauw Technique was determined to be 1.3×10-6 Ω·m. Raman spectroscopy confirmed the absence of carbon or graphite phases in the laser-induced doped diamond, indicating that the enhanced conductivity was due to phosphorus incorporation.Furthermore, p-type doped single crystal diamonds were successfully prepared by introducing boron during the growth process using Microwave Plasma Chemical Vapor Deposition（MPCVD）. It was demonstrated that the proposed technique can introduce impurities into single crystal diamonds to form doped conductive thin layers, which has potential applications in the field of microdevices and integrated circuits.

This volume contains the proceedings of the 14th International Conference on Ion Beam Modification of Materials, IBMM 2004, and is published by Elsevier-Science Publishers as a special issue of Nuclear Instruments and Methods B. The conference series is the major international forum to present and discuss recent research results and future directions in the field of ion beam modification, synthesis and characterization of materials. The first conference in the series was held in Budapest, Hungary, 1978, and subsequent conferences were held every two years at locations around the Globe, most recently in Japan, Brazil, and the Netherlands. The series brings together physicists, materials scientists, and ion beam specialists from all over the world. The official conference language is English. IBMM 2004 was held on September 5-10, 2004. The focus was on materials science involving both basic ion-solid interaction processes and property changes occurring either during or subsequent to ion bombardment and ion beam processing in relation to materials and device applications. Areas of research included Nanostructures, Multiscale Modeling, Patterning of Surfaces, Focused Ion Beams, Defects in Semiconductors, Insulators and Metals, Cluster Beams, Radiation Effects in Materials, Photonic Devices, Ion Implantation, Ion Beams in Biology and Medicine including New Materials, Imaging, more » and Treatment. « less

Introduction. Section A: AO/UV and Radiation Effects on Materials and Structures in the LEO Space Environment. Low Flux Atomic Oxygen: Can it Be More Hazardous than High Flux? A Risk Assessment Study Y. Haruvy. Atomic Oxygen Durability Testing of an International Space Station Solar Array Validation Coupon M.J. Forkapa., et al. A Technique for Synergistic Atomic Oxygen and Vacuum Ultraviolet Radiation Durability S.K. Rutledge, B. Banks. Atomic Oxygen Durability of Second Surface Silver Microsheet Glass Concentrators K.K. de Groh, et al. A Study of Atomic Oxygen Material Degradation by Spaceflight Experiments and Ground-Based Simulation I.L. Harris, et al. Laboratory Simulation of Low Earth Orbit C.L. Bungay, et al. Section B: Interaction of Matter with LEO Environment. Prediction of In-Space Durability of Protected Polymers Based on Ground Laboratory Thermal Energy Atomic Oxygen Testing B. Banks, et al. Ground-Based Experimental Verification of the Predictive Model of Polymer-Based Materials Erosion by Atomic Oxygen in LEO G.R. Cool, et al. Anomalous Behaviour of the Linear Expansion Coefficient of Reinforced Plastics at Increased Temperatures R. Tourussov, et al. Predictive Models of Erosion Processes in LEO Space Environment: A Basis for Development of an Engineering Software J.I. Kleiman, et al. Section C: Large Scale Coating Process Developments for Protection in LEO. The Strategic Technologies for Automation And Robotics (Stear) Program: Protection of Materials in the Space Environment Sub-Program C. Brunet, et al. Plasma-Deposited Coatings for the Protection of Spacecraft Material Against Atomic Oxygen Erosion G. Czeremuszkin, et al. Large-Scale Electron Cyclotron Resonance Deposition of Protective Coatings for Space Applications R.V. Kruzeiecky, et al. Development of High Diffuse Reflectance Surfaces on Teflon J.I. Kleiman, et al. Materials Exposure in Low Earth Orbit 2 (MELEO2): An Update E. Poire, et al. Protection of the Radarsat Spacecraft from the Low Earth Orbit Environment D. Zimcik, S. Ahmed. Section D: Synthesis and Modification of Materials and Surfaces for Protection in LEO. About Some Aspects of Changing Optical Properties of Glass in Solar Arrays and Other Space Materials on Exposure to LEO Space Environment V.G. Tikhii. Photosil(t) -- A New Surface Modification Technique for Erosion Resistance Improvement of Polymer-Based Materials in LEO J.I. Kleiman, et al. Soft X-Ray Radiation as a Factor in the Degradation of Spacecraft Materials A. Milintchouk, et al. Surface Modification of Polymer-Based Materials by Ion Implantation: A New Approach for Protection in LEO Z.A. Iskanderova, et al. TOR and COR AO-VUV Resistant Polymers for Space A. Shepp, et al. Appendix A: Organizing Committee. Index.

Nitrogen doping of diamond by ion implantation

First principle study of the attachment of graphene onto non-doped and doped diamond (111)