The effect of silicon ion implantation on the structure of tantalum–silicon contacts (original) (raw)
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Analysis of annealing and ion implantation effects in Ti/TiN contacts on silicon
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1990
The effects of thermal annealing and 350 keV As+ ion implantation on interdiffusion processes in a c-Si/Ti/TiN system were analysed. The Ti/TiN contacts were deposited by sputtering (Ti, 100 nm) and by reactive sputtering (TiN, 50 nm) on (111) n-Si wafers. Characterization included RBS, SEM and XRD analysis and electrical measurements. During vacuum annealing, interdiffusion is observed at the Si/Ti
Characterization of ion-implanted Si by electronic and structural data
Nuclear Instruments and Methods in Physics Research, 1983
Si ~111) was ion implanted with ions of various masses (11B +, 2~Si ~ 31p. 75As~ and I zLSb') with different energies. The damaged layer was measured by UPS, RBS and optical methods. The electronic structure of ttB + and 31 p+ differed. The damage profile of the ion implanted layer is not stepqike for all implanted ions and it has a double peak for liB ~ as given by electronic data. These results are only partly consistent with the structural results given by RBS.
Effects of C+ ion implantation on electrical properties of NiSiGe/SiGe contacts
Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms, 2013
We have investigated the morphology and electrical properties of NiSiGe/SiGe contact by C + ions preimplanted into relaxed Si 0.8 Ge 0.2 layers. Cross-section transmission electron microscopy revealed that both the surface and interface of NiSiGe were improved by C + ions implantation. In addition, the effective hole Schottky barrier heights (U Bp ) of NiSiGe/SiGe were extracted. U Bp was observed to decrease substantially with an increase in C + ion implantation dose.
Investigation of inhomogeneous structures of near-surface-layers in ion-implanted silicon
The ion implantation as a subject of investigations attracts increasing interest because of its technological applications. For example, the ion implantation and the adequate thermal treatment are the basic processes for fabrication of a new so-called delta-BSF solar cell. In this silicon solar cell, the continuous sub-structure of modified material _planar amorphous-like layer of nanometric thickness with very thin transition zones. is inserted into the single-crystal emitter. From earlier high resolution electron microscopy studies, it is evident that these two Si phases coexist in the form of well-defined layers separated by sharp heterointerfaces wZ.T. Kuznicki, J. Thibault, F. Chautain-Mathys, S. De Unamuno, Towards ion beam processed single-crystal Si solar cells with a very high efficiency, E-MRS Spring Meeting, Strasbourg, France, First Polish–Ukrainian Symposium, New Photovoltaic Materials for Solar Cells, October 21–22, Krakow, Poland, 1996.x. The aim of this paper is the further structural characterisation of silicon single crystal with buried ‘amorphous’ layer. The non-destructive X-ray diffraction methods as well as the transmission electron microscopy were used to investigate the quality of the a-Sirc-Si heterointerfaces, structural homogeneity of the layers and distribution of the stress field. The measurements were carried out on an initial, as-implanted and annealed material. The _100:-oriented Si single crystals were implanted with 180 keV energy P ions at room temperature.
Silicided Shallow Junction Formation Using Ion Implantation and Thermal Annealing
MRS Proceedings, 1988
The combination of arsenic and boron implantation with rapid thermal annealing (RTA) has been investigated to form shallow p-n junctions under a titanium silicide (TiSi 2 ) metallization. The use of TiSi 2 as a connection material can lead to the destruction of the junction if the kinetics of silicidation and doping are not well controlled. The purpose of this study is to better understand and control these kinetics, using far-from equilibrium processing such as ion implantation and RTA. The structures were characterized by Rutherford Backscattering Spectometry (RBS) for arsenic and silicide profiling, Secondary Ion Mass Spectometry (SIMS) for boron profiling, Scanning Electron Microscopy (SEM), and electrical sheet resistance measurements. Two procedures were investigated. Both involved the thermal reaction of Ti thin films, sputter-deposited with thicknesses ranging between 40 and 80 nm. In the first experiment, the as-deposited films were implanted with either 115 keV arsenic or 28 keV boron to form the junction, disperse the native oxide, and ion beam mix the Ti and Si. The films were then subjected to an RTA at 750'C for 15 to 60 seconds, which leads to TiSi 2 formation in unimplanted films. Implantation was found to actually prevent TiSi 2 formation. Ion transport calculations indicated that dopant pile-up at the interface might inhibit silicidation while higher energies and larger implant doses can more effectively ion beam mix Ti and Si. A more attractive solution consists of first forming TiSi 2 from the as-deposited Ti by RTA, and then implanting to form the junction. This resulted in better control of the junction thickness. A sharp increase in the TiSi 2 resistivity was found after implantation but the original value could be restored by a second RTA. This RTA also electrically activated the dopants and recrystallized the junction. The material properties of Ti/Si and TiSi 2 /Si under ion bombardment, RTA, doping, and conventional furnace annealing will be discussed.
Surface and Coatings …, 2009
Silicon oxynitride (Si x O y N z) buried layers were synthesized by high fluence (≥ 1 × 10 17 ions-cm − 2) ion implantation of O + and N + sequentially into single crystal silicon at 150 keV to produce silicon-on-insulator (SOI) structures. The structures of the SOI devices were analyzed by FTIR and XRD measurements and the surface modification by using atomic force microscopy (AFM). The FTIR measurements on the implanted samples (≤ 1× 10 18 ion-cm − 2) show a single absorption band in the wavenumber range 1300-750 cm − 1 attributed to the formation of silicon oxynitride bonds in silicon. The integrated absorption band intensity is found to increase with increase in the fluence. The samples with nitrogen-oxygen sequence of implantation showed nitrogen-rich oxynitride formation whereas samples with oxygen-nitrogen sequence resulted in oxygen-rich oxynitride. The formation of separate phases of Si-O and SiN bonds was observed at high fluence level (≅ 2 × 10 18 ions-cm − 2). The XRD studies show the formation of mixed phases of Si 2 N 2 O and SiO 2 in the sample. The structures of the ion beam synthesized silicon oxynitride layers are found to be strongly dependent on the sequence of implantation. The surface roughness is observed to be very small at lower fluences and it increases as we go to high fluence levels due to heavy damage caused by implantation. The conical hill like structures on the silicon surface is seen due to heavy surface swelling and sputtering phenomena.
Titanium doped silicon layers with very high concentration
Journal of Applied Physics, 2008
Ion implantation of Ti into Si at high doses has been performed. After laser annealing the maximum average of substitutional Ti atoms is about 10 18 cm −3 . Hall effect measurements show n-type samples with mobility values of about 400 cm 2 / V s at room temperature. These results clearly indicate that Ti solid solubility limit in Si has been exceeded by far without the formation of a titanium silicide layer. This is a promising result toward obtaining of an intermediate band into Si that allows the design of a new generation of high efficiency solar cell using Ti implanted Si wafers.