The damage and strain induced by irradiation of both relaxed and pseudomorphic Ge,Si,-, films on Si(100) with 100 keV 28Si ions at room temperature have been studied by MeV 4He channeling spectrometry and x-ray double-crystal diffractometry. The ion energy was chosen to confine the major damage to the films. The results are compared with experiments for room temprature Si irradiation of Si( 100) and Ge( 100). The maximum relative damage created in low-Ge content films studied here (x=10%, 13%, 15%, 20%, and 22%) is considerably higher than the values obtained by interpolating between the results for relative damage in Si-irradiated single crystal Si and Ge. This, together with other facts, indicates that a relatively small fraction of Ge in Si has a significant stabilizing effect on the retained damage generated by room-temperature irradiation with Si ions. The damage induced by irradiation produces positive perpendicular strain in Ge,Si, --x, which superimposes on the intrinsic positive perpendicular strain of the pseudomorphic or partially relaxed films. In all of the cases studied here, the induced maximum perpendicular strain and the maximum relative damage initially increase slowly with the dose, but start to rise at an accelerated rate above a threshold value of -0.15% and 15%, respectively, until the samples are amorphized. The pre-existing pseudomorphic strain in the Ge,Sii-, film does not significantly influence the maximum relative damage created by Si ion irradiation for all doses and x values. The relationship between the induced maximum perpendicular strain and the maximum relative damage differs from that found in bulk Si( 100) and Ge( 100).

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Influence of lattice strain on charge/orbital ordering and phase separation in Pr0.7(Ca0.6Sr0.4)0.3MnO3 thin films

The chemical etchant composed of hydrofluoric acid, hydrogen peroxide, and acetic acid (HF:H202:CH3COOH) is studied as a selective etchant of SiGe over St. It is found that the solution has a very high selectivity of etching SiGe over St. Etch rates for various GexSil x samples with differing mole fractions of Ge (0.15 -< x -< 0.40) are discussed as well as the stopping behavior of the solution on St. Also discussed is the application of the solution to heterostructure devices, particularly the three terminal resonant tunneling transistor.

Damage and strain produced in a 370-nm-thick strained epitaxial Ge0.10Si0.90 film on Si(100) by irradiation with 320 keV 28Si+ ions at fixed temperatures ranging from 40 to 150 °C and for doses from 1 to 30×1014/cm2 have been measured by MeV 4He channeling spectrometry, transmission electron microscopy, and high-resolution x-ray diffractometry. The ion energy was chosen so that the maximum damage created by irradiation occurs very near the GeSi-Si interface. For all temperatures, the retained damage and the perpendicular strain induced by the irradiation are significantly greater in the GeSi epilayer than in the Si substrate. For all doses the retained damage and the induced perpendicular strain become small above 100 °C. Both rise nonlinearly with increasing ion dose. They are related to each other differently in GeSi than in bulk Si or Ge irradiated at room temperature. Postirradiation furnace annealing can remove a large portion of the induced damage and strain for nonamorphized samples. Amorphized samples regrow by solid-phase epitaxy after annealing at 550 °C for 30 min; the regrown GeSi is, however, highly defective and elastically relaxed. A consequence of this defectiveness is that irradiation-induced amorphization in metastable GeSi is undesirable for applications where good crystalline quality is required. Ion implantation above room temperature can prevent amorphization.

Enhanced surface cation mobility on Sn deltadoped (Ga,Al)As Appl.

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