Filling 4H-SiC trench towards selective epitaxial growth by adding HCl to CVD process

Abstract

In this study, 4H-SiC stripe-shaped trenches preformed on an n + substrate were filled by adding HCl to the chemical vapor deposition process at relatively high pressures. HCl was found capable of counterbalancing the deposition on the mesa top by strong etching, and it thus enabled quasiselective epitaxial growth across the whole extents of the trenches, where the epilayer preferentially grows from the trench bottom. Using the established technique, the 1-µm-wide 4H-SiC trenches, with an aspect ratio of 5, which is the highest aspect ratio to date, were completely filled at a growth rate above 0.5 µm/h and acquired a flat end surface.

Excellent potential of photo-electrochemical etching for fabricating high-aspect-ratio deep trenches in gallium nitride

“…We therefore used SiC trench structures fabricated by ICP-RIE as our reference structures. 5,32,33) In Fig. 5, the solid, dashed, and dotted lines correspond to estimates of the aspect ratio of PEC etching based on W r =(W mask + 2W side-etching ), where W mask is the width of the Ti etching mask and W side-etching is the amount of side etching.…”

“…We commit to sharing this convenient PEC etching technology with the GaN community as part of our responsibility as a supplier of GaN substrates. SiC [5] SiC [33] Fig. 5.…”

Numerical analysis of the Gibbs–Thomson effect on trench-filling epitaxial growth of 4H-SiC

“…1). In this model that assumes perfect equilibrium, the effects of etching SiC by H 2 , 9) HCl, 10) and their related species are automatically included in C e Si and C e C . In accordance with the two-dimensional GT theory, 11) the equilibrium gas-phase concentration of growing species that are in contact with a curved surface with r is expressed as C e ðrÞ ¼ C e ð1Þ exp…”

“…The n-type trenches were halffilled with p-type 4H-SiC by adding 100 sccm HCl to a horizontal hot-wall reactor using 3 sccm SiH 4 , 1 sccm C 3 H 8 , and 80 slm H 2 . 10) The growth was carried out at a T s of 1873 K for 3 h under a total pressure P of 26 kPa. The sample position from the front edge of the susceptor (x) was 10 cm and the mean gas velocity (v) was 25 cm=s at room temperature.…”

Photoelectrochemical Etching Technology for Gallium Nitride Power and RF Devices

“…Previously reported GaN trench depths were approximately 1-3 μm with aspect ratios of 1-3. We therefore used SiC trench structures fabricated by ICP-RIE as our reference structures [23][24][25]. In Fig.…”