Understanding pressure-induced phase-transformation behavior in silicon through in situ electrical probing under cyclic loading conditions

Abstract

Cyclic indentation of crystalline silicon exhibits interesting pressure-induced phase-transformation behavior whereby sequential changes in the phase composition ultimately lead to a catastrophic ͑"pop-out"͒ event during subsequent cycles and complete transformation to high pressure Si-III and Si-XII phases. This study combines in situ electrical measurements with cyclic loading to monitor such phase-transformation behavior. We find that, if a pop-out is not observed on the unloading curve, the end phase is predominantly amorphous but a small and increasing volume of Si-III/Si-XII results with each cycle. At a critical Si-III/Si-XII volume, pop-out can occur on a subsequent cycle, whereafter Si-III/Si-XII dominates the indent volume.

Nanoindentation of Silicon and Germanium

“…In addition to the clear delineation between r8/bc8 and a-Si end phases based on unloading rate, there are some indentation conditions, such as intermediate unloading rates (Ruffell et al, 2007a), the use of sharp Berkovich indenters (Ruffell et al, 2007a(Ruffell et al, , 2009a, and cyclic loading/ unloading (Fujisawa et al, 2007(Fujisawa et al, , 2009, where Raman data and unloading Figure 3 Raman spectra for both slow and fast unloading rates showing different phase transformation pathways, with a Raman spectrum of dc-Si for comparison. Indents were made under the same loading conditions using a 20-μm radii spherical indenter with a maximum load of 700 mN and a loading rate of $5 mN/s.…”

Mechanical properties of nanocrystalline deformed layers induced by nanogrinding of CdZnTe single crystals

“…Therefore, the three deformed layers induced by nanogrinding have Philosophical Magazine Letters 189 higher values of hardness than perfect single crystals. This is different from the situation of hard-brittle Si semiconductor materials, where deformed layers were found to be softer than those of the single crystals [16][17][18]. For a comparison between CZT and Si semiconductor materials, loading-unloading curves of Si are shown in the inset of Figure 1a.…”

“…During CZT device fabrication, nanogrinding is required to remove the deformed layers of CZT wafers sliced from an ingot [3,11]. Deformed layers induced by machining significantly affect the mechanical, optical, and electrical properties of both soft-brittle CZT [12][13][14] and hard-brittle silicon (Si) [15][16][17][18][19][20][21][22] semiconductor materials, such as silicon (Si), germanium, and gallium arsenide, generated by mechanical machining [3] and so are likely to have distinct mechanical properties.…”

A tension stress loading unit designed for characterizing indentation response of single crystal silicon under tension stress

“…Mechanical properties of single crystal silicon are key issues in these research works. [1][2][3][4][5] Kinds of testing methods have been developed to characterize mechanical properties of single crystal silicon in mm ∼ nm scales, such as micro/nano-indentation testing, 6-8 scratch testing, 9,10 cyclic loading testing, 11,12 microcompression testing, 13 microbending testing 14 as well as combined in situ testing and analysis methods. 15,16 Among these testing methods, micro/nano-indentation testing plays a very important role for characterizing mechanical properties of single crystal silicon because of its high testing resolution and nearly non-destructive testing.…”