Mechanical Behavior of Undoped n-Type GaAs under the Indentation of Berkovich and Flat-Tip Indenters

Abstract

In this research, the mechanical behavior of undoped n-type GaAs was investigated by nanoindentation experiments using two types of indenters—Berkovich and flat-tip—with force applied up to 1000 mN. From the measured force-depth curves, an obvious pop-in phenomenon occurred at force of 150 mN with the flat-tip indenter representing elastic–plastic transition. The Young’s modulus and hardness of GaAs were calculated to be 60–115 GPa and 6–10 GPa, respectively, under Berkovich indenter. Based on the observation of indent imprints, the fracture characteristics of GaAs were also discussed. A recovery of crack by the next indentation was observed at 1000 mN with Berkovich indenter. In the case of flat-tip indentation, however, surface material sank into a wing shape from 400 mN. In this sinking region, a density of fork-shaped sinking, slip lines, and crossed pits contributed to the slip bands, and converging crossed twinning deformations inside the GaAs material were generated. Since cracks and destructions on GaAs surface took place more easily under the flat-tip indentation than that of Berkovich, a machining tool with a sharp tip is recommended for the mechanical machining of brittle materials like GaAs.

Molecular dynamics simulation of AFM tip-based hot scratching of nanocrystalline GaAs

“…(a). It became evident that the magnitude of von Mises stress in the cutting zone was ~6.89 GPa, which appeared close to the experimental nanoindentation hardness[37][38] of GaAs. The result shows that both the von Mises and the minor Principal stress criterion can be used to predict yielding during ductile-mode cutting of GaAs.Variations of the average hydrostatic stress and vonMises stress at different cutting temperatures are shown in Fig.…”

Fracture surface analysis and quantitative characterization of gallium arsenide III-V semiconductors using fractography

“…10). These are in good agreement with another reported surface instability previously reported in GaAs ("fork-shaped" sinking 44 ) and analogous to "V-shape markings" in single crystal silicon 20,45 .…”

Influence of Si Doping on Dislocations and Mechanical Properties of GaAs Crystals Grown by Modified Vertical Bridgman Method

“…Here, the h max is the maximum indentation depth on the F – h curve and the A ( h c ) is the contact area corresponding to the maximum indentation depth. [ 43–45 ] When the maximum indentation depth occurs, the projected area of contact can be determined from the geometry of the indenter. The experiment was repeated eight times for each crystal plane, and the calculated elastic modulus is shown in Figure .…”

“…[ 42 ] Varied Young's modulus and hardness of (100) GaAs have been reported in refs. 43 and 45. The hardness of (001) GaAs decreased from 4 GPa at room temperature to 0.5 GPa at 500 °C.…”