Recovery Of Implantation Damage Research Articles

Optical study of implantation damage recovery from Si-implanted GaN

Comprehensive and systematic optical activation studies of Si-implanted GaN grown on sapphire substrates have been made as a function of ion dose and anneal temperature. Silicon ions were implanted at 200 keV with doses ranging from 1×10 13 to 5×10 15 cm −2 at room temperature. The samples were proximity cap annealed from 1250 to 1350 °C with a 500-Å-thick AlN cap in a nitrogen environment. The results of photoluminescence measurements made at 3 K show a very sharp neutral-donor-bound exciton peak along with a sharp donor–acceptor pair peak after annealing at 1350 °C for 20 s, indicating excellent implantation damage recovery. The results also indicate the AlN cap protected the implanted GaN layer very well during high temperature annealing without creating any significant anneal-induced damage. This observation is consistent with the electrical activation results for these samples.

Annealing studies of Si‐implanted Al 0.25 Ga 0.75 N

Electrical and optical activation studies of Si-implanted Al0.25Ga0.75N grown on sapphire substrate have been made as a function of ion dose and anneal temperature. Silicon implantation was done at room temperature with doses of 1 × 1014 and 1 × 1015 cm−2 at 200 keV. The samples were proximity cap annealed from 1200 to 1350 °C with a 500-Å-thick AlN cap in a nitrogen environment. The electrical activation efficiencies of 65 and 87% were obtained for the Al0.25Ga0.75N sample implanted with doses of 1 × 1014 and 1 × 1015 cm−2, respectively and annealed at 1350 °C for 2 min. The activation efficiency and mobility increase with anneal temperature, indicating an improved implantation damage recovery. The highest mobility obtained from the Si-implanted Al0.25Ga0.75N was 50 cm2/Vs for a dose of 1 × 1015 cm−2. The increase of photoluminescence intensities of band-edge luminescence and a broad green band was observed as the anneal temperature increases from 1200 to 1350 °C, indicating an excellent implantation damage recovery with increasing anneal temperature. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

High-Sensitivity Ion Beam Analytical Method for Studying Ion-Implanted SiC

Abstract. The combination of Backscattering Spectrometry and channeling with the 12 C(,) 12 C nuclear resonance at 4.26 MeV to study radiation damage in the carbon sublattice of 6H-SiC was applied. 6H SiC samples were implanted with 200 keV Al ions in a dose range of 410 14 cm -2 - 110 16 cm -2 with different current densities at room temperatures. The implanted samples were annealed at 1200oC in argon for 1 hour. In the case of low dose, low current density implantation damage recovery seems to be complete. Introduction Silicon carbide is a wide bandgap semiconductor material with many advantages for high temperature, high power and high frequency applications. Its local doping can only be performed by ion implantation, due to the very low diffusivity of the dopants in SiC, even at high temperatures. However, an equivalent ion beam irradiation creates more damage in the crystal lattice of SiC than it would be in Si. Moreover in the case of SiC the damage creation depends not only the dose of implanted atoms, but on the ion current during implantation [1]. The damage process and the structural recovery after a further high temperature annealing are not yet fully understood. Ion beam analytical methods are suitable for observing ion implantation damage. Widely used Rutherford Backscattering method with channeling (BS/C) provides information on the damage only in the silicon sublattice since the small signals from carbon are situated on the high background of silicon. In our present work the 4.26 MeV

Conductivity behaviour of Cr implanted TiO 2

In its pure state rutile is an insulator with a 3 eV band gap. Its electrical conductivity, less than 10 −13 Ω −1 cm −1, can be enhanced up to more than 12 orders of magnitude by reduction or doping. In this work we study the doping of [0 0 1] TiO 2 single crystals with chromium ions implanted with 140 keV at room temperature and fluences of the order of 10 17–10 18 ions/cm 2. Implantation damage and damage recovery were accessed using the Rutherford backscattering technique in the channeling mode. Electrical resistivity measurements were performed as a function of temperature between 5 and 300 K. Upon implantation the implanted region becomes completely disordered and displays an enhanced electrical conductivity with a variable range hopping behaviour. After annealings at temperatures up to 1300 K, the lattice recovers and the implanted Cr moves out of the implanted region. The electrical conductivity behaviour changes from variable to fixed range hopping and after the 1300 K annealing becomes typical of a thermally activated semiconductor with 0.36 eV activation energy.

Ion implantation and annealing of diamond studied by emission channeling and cathodoluminescence

Abstract We review emission channeling (EC) studies to determine the lattice sites of radioactive impurities in IIa diamond after low dose room temperature implantation and subsequent annealing. The recovery of implantation damage was studied after implantation of 111 In and 73 As. Two distinct annealing stages, one in the temperature interval 300–600 K and the other at 1200 K were observed. The lattice sites of the potential donor 8 Li, 33 P and 73 As atoms were studied. Li occupies mainly tetrahedral interstitials sites, however, a smaller substitutional fraction is presumably due to replacement collisions occurring during implantation. Significant Li diffusion does not take place up to 900 K. EC measurements reveal high substitutional fractions for P and As of 70(10)% and 55(5)%, respectively. Complementary to the EC studies, cathodoluminescence (CL) studies of the optical properties of implanted diamond are especially suited to determine the electrical activation of implanted impurities. This is demonstrated with CL measurements of B and P implanted diamond. Finally, the feasibility of EC studies using the potential donor atoms Na, S, and Se is discussed.

Lattice Sites and Stability of Implanted Er in FZ and CZ Si

AbstractWe report on the lattice location of 167Er in Si measured by conversion electron emission channeling. In both FZ and CZ Si, a high fraction of Er (>65%) occupies near-tetrahedral interstitial (T) sites directly following 60 keV room temperature implantation at doses of 6× 1012 cm−2 For higher doses, the as-implanted near-T fractions of Er visible by emission channeling are smaller, due to the beginning of amorphization. Following the recovery of implantation damage at 600°C, more than 70% of Er is found on near-T sites in both FZ and CZ Si. In FZ Si, Er exhibits a remarkable thermal stability and only prolonged annealing for several hours reduces the near-T fraction. On the other hand, annealing of CZ Si at 900°C for more than 10 minutes results in the majority of Er probes in sites of very low symmetry or disordered surroundings.

Optical activation of ion implanted and annealed GaN

Ion implantation and the associated annealing was investigated using luminescence and absorption measurements to demonstrate the efficacy of implantation for introducing various classes of dopants into GaN. A wide range of implantation and annealing studies were performed with several dopant species (Zn, Nd, Er, Ar). Room temperature ion implantation was performed on MOCVD grown GaN samples at energies between 200 and 400 keV with doses ranging from 1 × 1013 to 1 × 1015 cm−2. Conventional furnace annealing in flowing NH3 or N2 resulted in good recovery of implantation damage at an annealing temperature of 1000°C for 90 min. However, surface degradation became evident for annealing in an NH3 environment at temperatures above 1000°C. Low temperature photoluminescence showed that the optical activation of the Zn, and the rare earth elements, Er and Nd, was optimum in the NH3 annealing environment at 1000°C.

Room-temperature luminescence in semi-insulating polycrystalline silicon implanted with Er

We demonstrate sharp room-temperature electroluminescence at 1.54 μm due to intra-4f transitions of Er 3+ in semi-insulating polycrystalline silicon (SIPOS) implanted with Er and annealed for implant damage recovery. Our measurements refer to SIPOS containing ≈ 30 at.% O, doped with Er to concentrations of about 1 at.% and annealed at a temperature in the 400–1100°C range. The luminescence has been excited either by optically pumping with an Ar laser or by biasing suitable metal-SIPOS-p + silicon devices.

7259. Temperature and energy dependence of ion-beam synthesis of epitaxial Si/CoSi 2/Si heterstructures : K. Radermacher et al,J Appl Phys, 68, 1990, 3001–3008

Both structural and optical activation studies of Si-implanted Al0.18Ga0.82N have been made as a function of anneal temperature by using the x-ray rocking curve measurements and photoluminescence (PL) and time-resolved PL (TRPL) measurements. The full width at half maximum values of both (002) and (102) direction ω-rocking curves for the Si-implanted Al0.18Ga0.82N samples decrease as the anneal temperature increases from 1150 to 1250 ∘C. The peak widths of the rocking curves for the as-implanted sample are much broader than those for the Si-implanted and annealed samples, indicating the implantation damage recovery after high temperature anneal. With increasing anneal temperature, the PL peak intensity increases and the PL decay becomes slower. The increase of PL intensity and recombination rate is attributed to both an increase of Si-donor activation and lattice damage recovery. These PL and x-ray results are very consistent with the results of anneal temperature-dependent electrical activation study.

7260. The influence of low copper doping concentrations on the recrystallization process in and the electrical properties of germanium in Ge:Cu thin film transistors: a

Both structural and optical activation studies of Si-implanted Al0.18Ga0.82N have been made as a function of anneal temperature by using the x-ray rocking curve measurements and photoluminescence (PL) and time-resolved PL (TRPL) measurements. The full width at half maximum values of both (002) and (102) direction ω-rocking curves for the Si-implanted Al0.18Ga0.82N samples decrease as the anneal temperature increases from 1150 to 1250 ∘C. The peak widths of the rocking curves for the as-implanted sample are much broader than those for the Si-implanted and annealed samples, indicating the implantation damage recovery after high temperature anneal. With increasing anneal temperature, the PL peak intensity increases and the PL decay becomes slower. The increase of PL intensity and recombination rate is attributed to both an increase of Si-donor activation and lattice damage recovery. These PL and x-ray results are very consistent with the results of anneal temperature-dependent electrical activation study.