Philosophical magazine · 1968 · 221 citations · 7 references
Materials ScienceAbstract Thin FilmsSingle CrystalsIon ImplantationEngineeringCrystalline DefectsPhysicsSurface ScienceApplied PhysicsSingle Event EffectsIon Bombardment DamageElectron MicroscopeDefect FormationThin FilmsAmorphous SolidIon EmissionSilicon Debugging
Thin films of n‑type and p‑type silicon contain ~50 Å disordered zones visible after ~10^13 Ne⁺ ions cm⁻² bombardment. This visual cue is used to determine the ion dose required to form amorphous silicon as a function of substrate temperature during bombardment. With increasing dose the zones overlap to form a continuous amorphous layer; annealing at 400–500 °C removes the zones, while ~630 °C recrystallizes the layer epitaxially, leaving dislocation loops and dipoles, and the regions appear milky when fully amorphous due to Rayleigh scattering.
Abstract Thin films of single crystals of both n-type and p-type silicon contain disordered zones ∼ 50 Å in diameter, discernible in the electron microscope after bombardment with ∼ 1013 Ne+ ions cm−2. As the dose increases these zones become more numerous until eventually (≳ 1014 ions cm−2) they overlap, creating a continuous surface layer which electron diffraction shows to be amorphous silicon. The individual zones disappear on annealing between 400 and 500°C, and at ∼630°C the amorphous layer recrystallizes epitaxially upon the underlying silicon, leaving an array of dislocation loops and dipoles. The bombarded regions exhibit various hues until eventually when they become completely amorphous they appear 'milky' due to the Rayleigh scattering of light. This appearance has been used as a convenient method to study the ion dose needed to form amorphous silicon as a function of the temperature of the silicon during bombardment.
7