C. Ascheron

A comparative study of swelling, strain and radiation damage of high-energy proton-bombarded GaAs, GaP, InP, Si and Ge single crystals

Abstract Swelling is studied on GaAs, GaP, InP, Si and Ge implanted with 0.3 and 1.2 MeV protons in the range of fluences D = 1015-8 × 1017cm−2, for several proton energies, implantation and annealing temperatures (T = 300–650 K). Within t the “buried” damaged layer all materials exhibit a volume dilation whereas in the near-surface layer only GaAs, GaP and Ge show considerable expansion and InP contracts due to the proton bombardment. For the interpretation of the results additional measurements of strain and damage density are taken into consideration.

In-situ determination of lattice expansion in proton-bombarded GaP single crystals

Abstract The lattice expansion of GaP, irradiated by 0.3–1.4 MeV protons at 140–715 K was studied in situ by means of the proton- induced Kossel effect. The measurements characterize the surface layer of the crystal with a thickness of 1–2μm. The increase of interplanar spacing Δd{111} measured at T ≥ RT follows a “sublinear” dose-relation with saturation at higher doses. The different initial slopes of the curves obtained at various incidence energies can be described by the energy dependence of the elastic displacement cross section. Measurements performed at T < RT exhibit a more linear “expansion-dose” dependence with a higher expansion rate. As shown by channeling backscattering analysis at RT, the damage density increases with the proton dose in the same manner as the lattice expansion. The expansion was also investigated using X-ray topographs and electron-induced Kossel patterns, confirming the in-situ results.

Study of proton-bombardment-induced radiation damage in elemental and compound semiconductors by RBS channeling

Abstract In selected A III B V , A II B VI and elemental semiconductors, which were bombarded with 0.3 MeV protons, the radiation damage is studied with the RBS channeling technique and compared to the theoretically determined primary damage profiles. It has been observed that the various material groups exhibit a different sensitivity to radiation damage. The sensitivity within each group scales approximately with the primary defect production rates resulting from TRIM calculations. The experimental damage profiles are described by the TRIM results concerning the depth and shape of the maxima. The fluence dependent saturation behaviour of point defect density indicates that defect recombination processes are important at room temperature. The higher degree of remaining defects in compounds is attributed to the formation of antisite defects.

Hydrogen incorporation behaviour and radiation damage in proton bombarded InP single crystals

Abstract In proton bombarded InP single crystals the incorporation behaviour of different hydrogen isotopes is studied in relation to implantation induced radiation defects. Investigations of the fluence dependence (D = 1016-1018 cm−2), of the depth profile and of the annealing behaviour (T an = 300–1000 K) of hydrogen incorporation and of damage density indicate that only a small fraction of the implanted hydrogen is chemically bonded to host lattice atoms. These bonded hydrogen atoms saturate dangling bonds at defect sites.

Hydrogen depth profiling in bevelled proton-implanted semiconductors by 4He ERDA and 19F NRA

Abstract In elemental and AIIIBV compound semiconductors the distribution of implanted hydrogen is studied and compared to theoretical distributions. The H depth profiles were revealed by bevelling and studied with the elastic recoil detection analysis (ERDA) and with the nuclear resonance reaction analysis (NRA). In this way, the applicability of both methods to investigations of deep profiles has been distinctly extended. It is found that the tetrahedrally coordinated semiconductors have a high H storaging capacity and that the implanted hydrogen has a low mobility due to the formation of hydrogen containing blisters.

Radiation damaging behaviour of GaP by MeV ion implantation

Abstract The creation of defects in GaP bombarded with energetic ions has been studied and compared with TRIM calculations. To investigate the influence of the relation of nuclear to electronic energy deposition and of the size of displacement cascades on defect production, the atomic species and projectile energies were varied from Z = 1 to 20 and E = 0.3 to 175 MeV. It has been found that not only the nuclear energy deposition but also the electronic energy deposition influences the defect production.

A simultaneous study of lattice expansion and swelling in proton-bombarded gap single crystals

Abstract The swelling and the lattice expansion of proton bombarded GaP single crystals are simultaneously measured for different proton doses by the “Talystep” method and by the Kossel technique, resp. The results reveal good agreement between the increase in interplanar spacing and the volume change in the damaged region