Macrosteps formation on 4H-SiC surfaces via Si melting within a sandwich configuration

From dissolution to controlled macrostepping of 4H-SiC during liquid Si-induced structuring in a sandwich configuration

“…This confirms the hypothesis of thermal gradient driven C transport from the SiC-bottom to the -top, with a dissolution rate of ̴ 0.8 µm/h. The deep depressions at the periphery of the wetted zone in Figure 3 are attributed to H 2 preferential etching of C atoms, as discussed in [11]. However, one should consider with care the determined value of dissolution rate because it was calculated by taking as zero reference the wafer level outside of the liquid.…”

“…We will thus assume that the area occupied by the liquid Si is equal to the surface of the SiC wafer, with no significant liquid overflow (as confirmed experiment before the experiment so that, from this mass calculate the Si thickness th Si between the two SiC pieces using the following equation: with d si the Si density (in g.cm -3 ), and S the area of the SiC was set to 30 µm since this was found to be the best condition for controlling the homogeneity of the process [11]. It was previously vertical thermal gradient inside the stack, leading to and on the optimization of the sandwich approach for regular used in this work for surface structuring of 4H-SiC type Si wafer is positioned between two 4H-SiC (0001) 4°off Si from SK Siltron company.…”

“…Such approach does not allow the processing of surfaces > ̴ 0.5 cm 2 so that it cannot be seriously considered as a device processing step. To solve this problem, a SiC/Si/SiC sandwich configuration, virtually allowing the possible processing of larger 4H-SiC areas, is being investigated by the authors [11,12]. The preliminary experiments were successful in terms of uniform spreading of the liquid Si and formation of highly step-bunched surfaces.…”

Создание темплейтов для гомоэпитаксиального роста 3C-SiC методом прямого сращивания пластин карбида кремния различающихся политипов

“…В настоящее время процесс взаимодействия карбида кремния с расплавами является предметом интенсивных исследований, но его механизм остается невыясненным. Однако недавно было показано, что на границе раздела твердой и жидкой фаз может происходить растворение ( " травление") поверхности пластин SiC по всей площади контакта, или взаимодействие может носить выраженный селективный характер, когда наиболее интенсивное растворение происходит в местах выхода структурных дефектов на поверхность SiC, граничащую с расплавом [25,26]. Отметим, что различные методы селективного травления (сухого, жидкостного, ex situ и in situ) успешно применяются в ростовых технологиях нитрида галлия с целью достижения эффекта ограничения распространения дефектов, содержащихся в подложках, в эпитаксиальные слои.…”

Templates for homoepitaxial growth of 3C-SiC obtained by direct bonding of silicon carbide wafers of differing polytype

“…At present, the process of interaction of silicon carbide with melts is the subject of intensive studies, but its mechanism remains unclear. However, it was recently shown that at the interface between the solid and liquid phases, dissolution ( " etching") of the surface of SiC wafers can occur over the entire contact area, or the interaction can be of a pronounced selective nature, when the most intense dissolution occurs in the places where structural defects appear on the SiC surface interfacing with the melt [25,26]. Note that various methods of selective etching (dry, liquid, ex situ and in situ) are successfully used in gallium nitride growth technologies in order to achieve the effect of limiting the propagation of defects contained in substrates in epitaxial layers.…”