The exceptionally large thermal strain in few-micrometers-thick 3C-SiC films on Si(111), causing severe wafer bending and cracking, is demonstrated to be elastically quenched by substrate patterning in finite arrays of Si micro-pillars, sufficiently large in aspect ratio to allow for lateral pillar tilting, both by simulations and by preliminary experiments. In suspended SiC patches, the mechanical problem is addressed by finite element method: both the strain relaxation and the wafer curvature are calculated at different pillar height, array size, and film thickness. Patches as large as required by power electronic devices (500-1000 μm in size) show a remarkable residual strain in the central area, unless the pillar aspect ratio is made sufficiently large to allow peripheral pillars to accommodate the full film retraction. A sublinear relationship between the pillar aspect ratio and the patch size, guaranteeing a minimal curvature radius, as required for wafer processing and micro-crack prevention, is shown to be valid for any heteroepitaxial system.

Albani, M., Marzegalli, A., Bergamaschini, R., Mauceri, M., Crippa, D., La Via, F., et al. (2018). Solving the critical thermal bowing in 3C-SiC/Si(111) by a tilting Si pillar architecture. JOURNAL OF APPLIED PHYSICS, 123(18) [10.1063/1.5019325].

Solving the critical thermal bowing in 3C-SiC/Si(111) by a tilting Si pillar architecture

Albani, M
;
Marzegalli, A;Bergamaschini, R;Miglio, L
2018

Abstract

The exceptionally large thermal strain in few-micrometers-thick 3C-SiC films on Si(111), causing severe wafer bending and cracking, is demonstrated to be elastically quenched by substrate patterning in finite arrays of Si micro-pillars, sufficiently large in aspect ratio to allow for lateral pillar tilting, both by simulations and by preliminary experiments. In suspended SiC patches, the mechanical problem is addressed by finite element method: both the strain relaxation and the wafer curvature are calculated at different pillar height, array size, and film thickness. Patches as large as required by power electronic devices (500-1000 μm in size) show a remarkable residual strain in the central area, unless the pillar aspect ratio is made sufficiently large to allow peripheral pillars to accommodate the full film retraction. A sublinear relationship between the pillar aspect ratio and the patch size, guaranteeing a minimal curvature radius, as required for wafer processing and micro-crack prevention, is shown to be valid for any heteroepitaxial system.
Articolo in rivista - Articolo scientifico
SiC; thermal strain; pillar; FEM
English
2018
123
18
185703
open
Albani, M., Marzegalli, A., Bergamaschini, R., Mauceri, M., Crippa, D., La Via, F., et al. (2018). Solving the critical thermal bowing in 3C-SiC/Si(111) by a tilting Si pillar architecture. JOURNAL OF APPLIED PHYSICS, 123(18) [10.1063/1.5019325].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/199305
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