Mechanical Deformation Induced in Si and GaN Under Berkovich Nanoindentation

Abstract

Details of Berkovich nanoindentation-induced mechanical deformation mechanisms of single-crystal Si(100) and the metal-organic chemical-vapor deposition (MOCVD) derived GaN thin films have been systematic investigated by means of micro-Raman spectroscopy and cross-sectional transmission electron microscopy (XTEM) techniques. The XTEM samples were prepared by using focused ion beam (FIB) milling to accurately position the cross-section of the nanoindented area. The behaviors of the discontinuities displayed in the loading and unloading segments of the load-displacement curves of Si and GaN thin films performed with a Berkovich diamond indenter tip were explained by the observed microstructure features obtained from XTEM analyses. According to the observations of micro-Raman and XTEM, the nanoindentation-induced mechanical deformation is due primarily to the generation and propagation of dislocations gliding along the pyramidal and basal planes specific to the hexagonal structure of GaN thin films rather than by indentation-induced phase transformations displayed in Si.

Effects of intra-crystalline microcracks on the mechanical behavior of a marble under indentation

“…5a), due to the brittle failure induced by the indenter (Fig. 5b), as also noticed in other brittle materials [23,24,25].…”

Berkovich indentation-induced deformation behaviors of GaN thin films observed using cathodoluminescence and cross-sectional transmission electron microscopy

“…According to the previous studies [7][8][9][10][11][12][13][14][15][16], we note here that the critically applied indentation load for direct identification of the multiple ''pop-in'' events in P-h curve is not only dependent on the type of indenters used, but also very much dependent on the test systems and the maximum indentation loads applied. Consequently, we reasonably deduce that these discrepancies are mainly owing to the various indentation methods used.…”

Nanomechanical Characterization of Brittle Rocks

“…11a) often exhibit pop-in phenomena, i.e. sudden discrete increase of the penetration depth at an approximately (14) H = P max A constant load, as also noticed in other materials (Jian 2007;Saber-Samandari and Gross 2009;Tulliani et al 2009). The pop-in is due to the formation of cracks, fractures around the indenter, as found by Presser et al (2010), because of the rock inhomogeneity even on the scale of hundreds of nanometers.…”