Implantation damage

As a start, Fig. 20 shows some profiles of total deuterium concentration after deuteration of samples prepared by implanting a fairly high concentration of phosphorus into moderately p-type material, with a subsequent high-temperature anneal to remove implantation damage. The different curves correspond to different times of deuteration at 150 °C. It is clear that for this family of cases, the data show just the early stages of penetration of the hydrogen into the p-type region. Data obtained from 200°C... 

Figure 4.18 (a) RBS and (b) AFM data of 4H-SiC implanted with Al at 700°C. Note the crystal quality is degraded due to implant damage, as expected. RBS and AFM data are courtesy of, respectively. Dr. Tami Isaac-Smith from the group under Professor John Williams at Auburn University and Dr. A. ]. Hsieh of the Army Research Laboratory. 

As described in Section 4.2.1, ion implantation damage is conveniently investigated by RBS-C and a substantial body of results is now available for SiC. From these data... 

Point defect production as a result of implantation damage of the kind shown in Figure 20 gives rise to anomalous B diffusion during subsequent annealing. A summary of recent models that explain these effects follows... 

B implants and low-temperature furnace annealing with transient diffusion that is associated with the activated removal of implant damage in the tail region of the implant. The magnitude of the enhanced, transient diffusivity increases with implant dose and energy but reaches saturation at 2 x 10 13 cm2/s. 

Low-dose B and P implants with RTA. Time-dependent diffusion is associated with annealing of implant damage. 

The fraction of the implant damage that anneals, fa, is assumed to depend directly on time at the annealing temperature ... 

Figure 25. Data and calculations showing the reverse diffusion effect from implantation damage annealing. As the RTA time increases, the amount of enhanced diffusion during the subsequent 800 °C furnace anneal decreases. Data are from Michel (51). (Reproduced with permission from reference 59. Copyright 1988 Institute of Electrical and Electronics Engineers, Inc.)...

The implant range dependence has been verified for B implants from 1 to 60 keV (Figure 27). Equation 56 is applied to the calculations until the implant damage has been annealed, and then Denh = 0. The maximum allowed value of Denh is 1.5 X 10 12 cm2/s. The damage anneal time criterion was derived from data that show initial rapid B diflusion during RTA and then a marked slow-down (51). 

Historically thermal annealing has been the method of removing implantation damage. Recently however, laser annealing has been pursued as an attractive alternative. Tsien, et al. 

Implantation with a variety of elements prooiuced a broad luminescence band around 2.15 eV [20], Implantation damage is likely to result in preferential creation of Ga-site defects indeed, the displacement energy threshold in III-V compounds tends to be lower for the cation site [21]. Formation of Ga vacancies is thus likely during implantation, consistent with the increase in the YL. 

The Mg-implanted samples in FIGURE 1 do not show a conversion to p-type material for any annealing temperature and closely track the unimplanted material. However, the Mg-samples coimplanted with P show a conversion from n-type to p-type at 1050°C with an increase in hole concentration at the high temperature. The success in realising p-type material with the P co-implanted samples is attributed to the P acting to either (a) create additional Ga-vacancies, via additional implantation damage, for the Mg to occupy as acceptors, or (b) reduce the number of N-vacancies and thereby also increase the probability of Mg occupying the preferred Ga-sublattice [4],... 

The 1150°C annealed sample PL is comparable to the reference except that its exciton luminescence has not recovered, which suggests that implant damage has not been fully removed by annealing. 

Headley TJ, Ewing RC, Haaker RF (1981) High resolution study of the metamict state in zircon. Proc 39 Annual Meeting Electron Microscopy Society of America, p 112-113 Headley TJ, Arnold GW, Northmp CJM (1982a) Dose-dependence of Pb-ion implantation damage in zirconolite, hollandite, and zircon. Mater Res Soc Symp Proc 11 379-387 Headley TJ, Ewing RC, Haaker RF (1982b) TEM study of the metamict state. Physics of Minerals and Ore Micrscopy—IMA 1982, p 281-289... 

Oliver WC, McCallum JC, Chakoumakos BC, Boatner LA (1994) Hardness and elastic modulus of zircon as a function of heavy-particle irradiation dose II. Pb-ion implantation damage. Radiation Effects Defects in Solids 132 131-141... 

Figure 11.5 shows the ion implantation damage distribution in Si following the 175 keV H implantation at a dose of 5 x 1016 H cirf2. The data is obtained from ion channeling experiments. The implantation damage peak is located at a depth of 1.41 pm. 

Figure 11.6 shows the hydrogen concentration in the sample as a function of sample depth as determined by ERD (Tesmer and Nastasi 1995). The H concentration peaks at a depth of 1.51 pm, somewhat deeper than the implantation damage peak. The ratio of the depth of the H concentration peak to the ion implantation damage peak is 1.06, consistent with the SRIM Monte Carlo simulations presented in Fig. 11.4. 

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