B. L. Darby

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

Nanostructured ion beam-modified Ge electrodes 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 Ge electrodes have great promise for use as high performance Li ion battery anodes.

Substrate orientation dependence on the solid phase epitaxial growth rate of Ge

The solid phase epitaxial growth process has been studied at 330 °C by transmission electron microscopy for Ge wafers polished at 10°–15° increments from the [001] to [011] orientations. The velocity showed a strong dependence on substrate orientation with the [001] direction displaying a velocity 16 times greater than the [111] direction. A lattice kinetic Monte Carlo model was used to simulate solid phase epitaxial growth (SPEG) rates at different orientations, and simulations compared well with experimental results. Cross sectional transmission electron microscopy and plan view transmission electron microscopy revealed stacking fault and twin defect formation in the [111] orientation where all other orientations showed only hairpin dislocations. The twin defects formed from Ge SPEG were comparatively less dense than what has previously been reported for Si, which gave rise to higher normalized velocities and a constant [111] SPEG velocity for Ge.

Role of nucleation sites on the formation of nanoporous Ge

The role of nucleation sites on the formation of nanoporous Ge was investigated. Three Ge films with different spherical or columnar pore morphologies to act as inherent nucleation sites were sputtered on (001) Ge. Samples were implanted 90° from incidence at 300 keV with fluences ranging from 3.0 × 1015 to 3.0 × 1016 Ge+/cm2. Electron microscopy investigations revealed varying thresholds for nanoporous Ge formation and exhibited a stark difference in the evolution of the Ge layers based on the microstructure of the initial film. The results suggest that the presence of inherent nucleation sites significantly alters the onset and evolution of nanoporous Ge.

Activation and thermal stability of ultra-shallow B+-implants in Ge

The activation and thermal stability of ultra-shallow B+ implants in crystalline (c-Ge) and preamorphized Ge (PA-Ge) following rapid thermal annealing was investigated using micro Hall effect and ion beam analysis techniques. The residual implanted dose of ultra-shallow B+ implants in Ge was characterized using elastic recoil detection and was determined to correlate well with simulations with a dose loss of 23.2%, 21.4%, and 17.6% due to ion backscattering for 2, 4, and 6 keV implants in Ge, respectively. The electrical activation of ultra-shallow B+ implants at 2, 4, and 6 keV to fluences ranging from 5.0 × 1013 to 5.0 × 1015 cm−2 was studied using micro Hall effect measurements after annealing at 400–600 °C for 60 s. For both c-Ge and PA-Ge, a large fraction of the implanted dose is rendered inactive due to the formation of a presumable B-Ge cluster. The B lattice location in samples annealed at 400 °C for 60 s was characterized by channeling analysis with a 650 keV H+ beam by utilizing the 11B(p, α)2α...

22 nm Node p+ USJ Formation Using PAI & HALO Implantation With Laser Annealing

Boron 200 eV p+ USJ dopant activation and junction leakage was studied with various combinations of PAI (Ge, B36, In & Xe) and HALO (As & Sb) implantation using msec laser annealing between 1220 °C and 1350 °C. For B only case without PAI or HALO, increasing laser anneal temperature from 1220 °C to 1350 °C improved dopant activation boron solid solubility (Bss) from 3E19/cm3 to 1.2E20/cm3 with excellent junction leakage below the lower detection limit of 10x due to residual implant damage (EOR defects) beyond the junction. Higher laser anneal temperatures up to 1350 °C improved junction leakage to below detection limit and Bss improved to 1.4E20/cm3. With deep Xe‐PAI junction leakage was severely degraded by 5 orders of magnitude to above the upper detection limit of >2.5E‐2A/cm2 but with annealing temperatures >1300 °C junction leakage improved, at 1350 °C junction leakage improved to 8...