Plasticity and deformation microstructure of 4H‐SiC below the brittle‐to‐ductile transition

Abstract

Compression tests under confining pressure are performed with a Paterson press in order to deform 4H-SiC plastically below the brittle-to-ductile transition temperature. Deformation microstructure in this regime is analysed using conventional and high resolution transmission electron microscopy and is compared with literature. Leading partial dislocations with carbon core and silicon core are observed on basal plane as well as perfect dislocations out of the basal plane. Double stacking faults are evidenced in the deformed microstructure. These original observations indicate that the deformation microstructures of 4H-SiC in the brittle domain are more complex than previously reported.

Defects created in N-doped 4H-SiC in the brittle regime: Stacking fault multiplicity and dislocation cores

“…Indeed, the dislocation dynamics are only known thanks to controversial theoretical and experimental results. Many experiments on the more common polytypes, 3C, 4H and 6H, give the lowest activation energy for silicon core partial dislocations (PDs) [1][2][3][4][5][6], whereas other studies show similar mobility for both carbon and silicon core PDs [7]. Note that the leading PDs were identified using the same technique [weak beam-dark field (WB-DF) imaging].…”

“…It concerns the multiplicity of the stacking faults (SFs) created in the brittle regime in highly N-doped 4H-SiC. Indeed, the identified defects consist of single stacking faults (SSFs) [2,4,5], double stacking faults (DSFs) [7] or multiple stacking faults (MSFs) [7,10]. The observed differences are particularly a matter of concern when the stacking is determined by high-resolution transmission electron microscopy (HRTEM).…”

Dislocation glide-controlled room-temperature plasticity in 6H-SiC single crystals

“…For higher-strength refractory materials such as SiC, a covalently bonded structural ceramic and a semiconductor, most of the existing literature is focused on the mechanical behavior of bulk crystals at elevated temperatures (T > 673 K) [3][4][5][6][7] as they are expected to be brittle at room-temperature. For example, high-temperature compression and bending of bulk 4H-SiC crystals revealed the existence of partial dislocations on the basal {0 0 0 1} planes, full dislocations out of the basal planes, and stacking faults due to the 4H to 3C transformation [8,9]. Roomtemperature measurements of indentation hardness [10][11][12] of bulk single-crystalline SiC and fracture strengths [13,14] of SiC nanorods and nanowires have helped identify the role of indenter geometry, crystal size and crystal orientation on the mechanical properties of SiC.…”

Reaction pathway analysis for differences in motion between C-core and Si-core partial dislocation in 3C-SiC

“…On the other hand, Pilyankevich et al (1982Pilyankevich et al ( , 1984 and Maeda et al (1988) attribute the different morphologies of partial dislocations to their Burgers vector. After that, Mussi et al (2007) and Lancin et al (2009) found that C-core partial dislocation could be either straight or zigzagged. Their experimental results showed that the core nature of partial dislocations cannot be deduced from the morphology of the dislocation line.…”

“…During the growth of 3C-SiC on silicon, lattice mismatch caused by the difference in lattice constant and thermal misfit due to the differences in thermal expansion coefficient will contribute to large residual stress (Nagasawa and Yagi., 1997, Sun, et al, 2012, Veprek, et al, 2009, Zielinski, et al, 2007, Severino, et al, 2007. This stress can induce a high dislocation density and wafer warpage in device manufacture.…”