Influence of As on the formation of mask-edge defects during stressed solid phase epitaxy in patterned Si wafers

The influence of As on the evolution of mask-edge defects during stressed solid phase epitaxy of two-dimensional Si⁺ pre-amorphized regions in patterned Si wafers was examined. Mask-edge defects∼60 nm deep formed at 525 °C for As⁺ implant energies of 7.5–50 keV with peak As concentration of ∼5.0×10²⁰ cm⁻³. Defect formation was attributed to an As-enhanced [110] regrowth rate relative to the [001] regrowth rate creating an amorphous/crystalline interface geometry favorable for defect formation. The similarity of mask-edge defect depths with As⁺ implant energy was attributed to surface retardation of [110] regrowth in shallow implants and enhanced [001] regrowth in deeper implants. Results indicate stress effects on regrowth rates are small compared to dopant effects

Interface stability in stressed solid-phase epitaxial growth

The role of applied stress on interface stability during Si solid-phaseepitaxialgrowth was investigated. Transmission electron microscopy observations of growthinterface evolution revealed in-plane uniaxial compression (tension) led to interface instability (stability). Additionally, level set simulations revealed that the stress-influenced interface instability was accurately modeled by adjusting the strength of the linear dependence of local interface velocity (rate of change of interface position with respect to time) on local interface curvature proposed in previous work. This behavior is explained in terms of tension in the growthinterface controlling interface stability during growth; it is argued that compressive (tensile) stress tends to reduce (enhance) interfacial tension and results in interfacial instability (stability) during growth.The authors acknowledge the Semiconductor Research Corporation for funding this work

Nanostructured ion beam-modified Ge films for high capacity Li ion battery anodes

Nanostructured ion beam-modified Geelectrodes fabricated directly on Ni current collector substrates were found to exhibit excellent specific capacities during electrochemical cycling in half-cell configuration with Li metal for a wide range of cycling rates. Structural characterization revealed that the nanostructured electrodes lose porosity during cycling but maintain excellent electrical contact with the metallic current collector substrate. These results suggest that nanostructured Geelectrodes have great promise for use as high performance Li ion battery anodes

Maximizing electrical activation of ion-implanted Si in In0.53Ga0.47As

A relationship between the electrical activation of Si in ion-implanted In₀.₅₃Ga₀.₄₇As and material microstructure after ion implantation is demonstrated. By altering specimen temperature during ion implantation to control material microstructure, it is advanced that increasing sub-amorphizing damage (point defects) from Si+ implantation results in enhanced electrical activation of Si in In₀.₅₃Ga₀.₄₇As by providing a greater number of possible sites for substitutional incorporation of Si into the crystal lattice upon subsequent annealing.The authors acknowledge the Semiconductor Research Corporation for funding this work

Synthesis of graphene and graphene nanostructures by ion implantation and pulsed laser annealing

In this paper, we report a systematic study that shows how the numerous processing parameters associated with ion implantation (II) and pulsed laser annealing (PLA) can be manipulated to control the quantity and quality of graphene (G), few-layer graphene (FLG), and other carbon nanostructures selectively synthesized in crystalline SiC (c-SiC). Controlled implantations of Si− plus C− and Au + ions in c-SiC showed that both the thickness of the amorphous layer formed by ion damage and the doping effect of the implanted Au enhance the formation of G and FLG during PLA. The relative contributions of the amorphous and doping effects were studied separately, and thermal simulation calculations were used to estimate surface temperatures and to help understand the phase changes occurring during PLA. In addition to the amorphous layer thickness and catalytic doping effects, other enhancement effects were found to depend on other ion species, the annealing environment, PLA fluence and number of pulses, and even laser frequency. Optimum II and PLA conditions are identified and possible mechanisms for selective synthesis of G, FLG, and carbon nanostructures are discussed

Kinetics and Morphological Instabilities of Stressed Solid-Solid Phase Transformations

An atomistic model of the growth kinetics of stressed solid-solid phase transformations is presented. Solid phase epitaxial growth of (001) Si was used for comparison of new and prior models with experiments. The results indicate that the migration of crystal island ledges in the growth interface may involve coordinated atomic motion. The model accounts for morphological instabilities during stressed solid-solid phase transformations.</p