Yan Xinshui

Range distributions of 50–400 keV Hg+in amorphous silicon and Si-Ar binary targets

Abstract Range distributions of 50–400 keV Hg + in amorphous Si and Si-Ar binary targets have been investigated by Rutherford backscattering spectrometry. The Si(100) wafers were amorphized by means of 150 keV Ar + irradiation to a dose of 2 × 10 15 ions/cm 2 . To produce Si-Ar binary targets, the Si(100) wafers were implanted with 150 keV Ar + to a dose of 3 × 10 17 ions/cm 2 . 50–400 keV Hg + were introduced into amorphous Si and Si-Ar binary targets in increments of 50 keV. Parallel scanning of the Hg + beams was used. The measured ranges and range stragglings have been compared to the Biersack theory. The results show that good agreements are found between the experimental and theoretical projected ranges for both Si and Si-Ar, but the predicted range straggling for both Si and Si-Ar are systematically lower than the experimental results in the case of a first order treatment. After correcting for second order energy loss terms, a better agreement for the range straggling is obtained.

Microstructure of copper films on silicon with an ion beam assisted deposited intermediate copper layer

Abstract Cu intermediate layers (IL) were deposited by ion beam assisted deposition (IBAD) on a Si(100) substrate before Cu surface films (SF) were deposited by electron gun and their effect on the microstructure of the Cu SF was studied. The argon ion energy and current density of IBAD were 2–20 keV and 45 μA cm 2 , respectively. The thickness of the Cu SF was 350 nm. The Cu SF, if there is no IBAD of Cu IL, have a strong preferential orientation of the Cu(200) plane parallel to the Si(100) surface. The IBAD of Cu IL changes this orientation to a (111) orientation. For an IBAD argon ion energy of 15 keV, the Cu SF has a maximum value of the X-ray diffraction (XRD) peak-height ratio, i.e. I(111) I(200) = 41 . Scanning electron microscope (SEM) analysis shows that the Cu films with Cu IL are rougher than those without Cu IL.