Anisotropic deformation of 4H-SiC wafers: insights from nanoindentation tests

Liu, XiaoShuang; Wang, Rong; Zhang, Junran; Lu, Yunhao; Zhang, Yiqiang; Yang, Deren; Pi, Xiaodong

doi:10.1088/1361-6463/ac9535

Cited by 15 publications

(2 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nanoindentation tests indicate that as the wafering proceeds, the hardness of the C face of a 4H-SiC wafer is always higher than that of the Si face, and the fracture toughness of the C face is always lower than that of the Si face. This means that the surface damage does not change the mechanical-property difference between the C face and Si face of 4H-SiC [22]. Given the lower fracture toughness of the C face of 4H-SiC, the thickness of the surface damage of the C face of a wire-sawed 4H-SiC wafer is higher than that of the Si face.…”

Section: Resultsmentioning

confidence: 99%

Optimizing the flatness of 4H-silicon carbide wafers by tuning the sequence of lapping

Zhang¹,

Liu²,

Wang³

et al. 2023

Semicond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

In this letter, we optimize the flatness of 4H silicon carbide (4H SiC) wafers by tuning the sequence-of single-sided lapping, enlightened by the different mechanical properties of the Si face and C face of 4H-SiC. After wire sawing, the coarse lapping and fine lapping are carried out to rapidly remove the surface damages and optimize the flatness of 4H-SiC wafers. From the point of view of controlling the values of the bow and warp of 4H-SiC wafers, the coarse-lapping sequence of the C-face lapping followed by Si-face lapping is beneficial, while the preferred fine-lapping sequence is Si-face lapping followed by C-face lapping. Nanoindentation tests indicate that the C face has higher hardness and lower fracture toughness the Si face. This gives rise to thicker surface damages at the C face after the wire sawing. After removing the same amount of wire-sawing induced surface damages, the thickness of residual surface damages of the C face is higher than that of the Si face after the coarse lapping. Since the fine lapping basically removes all the surface damages, and creates near-perfect C face and Si face. The higher amount of surface damages of the C face after the coarse lapping and the higher fracture toughness of the near-perfect Si face after the fine lapping can tolerate more plastic deformations, which gives rise to the superior flatness of the C-face followed-by-Si-- face coarse lapped and the Si-face-followed-by-C-face fine lapped 4H-SiC wafers, respectively.

show abstract

Section: Resultsmentioning

confidence: 99%

Optimizing the flatness of 4H-silicon carbide wafers by tuning the sequence of lapping

Zhang¹,

Liu²,

Wang³

et al. 2023

Semicond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Despite the recent surge of academic and industrial interests in 4H-SiC, many important aspects of its physical properties and the underlying physics are not clarified yet. For example, as a hexagonal crystal, anisotropy is expected for its physical properties like mechanical [7] and transport properties [1] such as carrier mobilities and Hall effect. The carrier mobil-ity is a key functional property that determines device performance such as on-resistance [8].…”

Section: Introductionmentioning

confidence: 99%

Phonon-limited carrier mobilities and Hall factors in 4H-SiC from first principles

Deng¹,

Yang²,

Pi³

2022

Preprint

View full text Add to dashboard Cite

Charge carrier mobility is at the core of semiconductor materials and devices optimization, and Hall measurement is one of the most important techniques for its characterization. The Hall factor, defined as the ratio between Hall and drift mobilities, is of particular importance.Here we study the effect of anisotropy by computing the drift and Hall mobility tensors of a technologically important wide-band-gap semiconductor, 4H-silicon carbide (4H-SiC) from first principles. With GW electronic structure and ab initio electron-phonon interactions, we solve the Boltzmann transport equation without fitting parameters. The calculated electron and hole mobilities agree with experimental data. The electron Hall factor strongly depends on the direction of external magnetic field B, and the hole Hall factor exhibits different temperature dependency for B c and B ⊥ c. We explain this by the different equienergy surface shape arising from the anisotropic and non-parabolic band structure, together with the energy-dependent electron-phonon scattering.

show abstract