14:15 〜 14:30
▼ [14p-2T-3] Chemical vapor deposition of hexagonal boron nitride (hBN) and its H2 induced anisotropic etching
キーワード：hexagonal boron nitride,CVD,Etching
Two-dimensional (2D) materials have attracted incredible research interest due to superior electronic and material properties compared to bulk form [1]. Due to its closer lattice resemblance with graphene and excellent dielectric property, hexagonal boron nitride (hBN) has been studied following the footsteps of graphene research.
In this work we report large area synthesis of hBN on Cu foil by chemical vapor deposition and its subsequent H2 etching to form highly directional triangular holes [2].Our system consist of single furnace with quartz tube as CVD chamber. Ammonia Borane was used as precursor kept away from growth zone during annealing to prevent early evaporation. During growth boat was moved closer to furnace to sublimate and evaporate precursor. As synthesized hBN was high quality and few layer demonstrated XPS, Auger, UV-IS and AFM analysis. After the growth precursor was moved away from furnace and hBN was subjected to etching. Different sets of experiment were carried out to study effect of temperature on etching mechanism. It was observed that at temperature < 9500C etching was isotropic visible only on grain boundaries and edges of crystal. But at higher temperature (≥9500C ) highly anisotropic etching was observed with triangular etched holes all over the crystal. Temperature dependent transition of isotropic to anisotropic etching can be explained from the fact that at higher temperature H2 solubility in Cu is increased many fold enabling H2 to move around the Cu and induce etching upon finding a defective hBN region. Controlled formation of triangular holes on hBN can serve as template for growing other 2D material like graphene for synthesis of inplane heterostructure. Variety of engineered 2D materials can be synthesized with desired electronic properties by choosing suitable combination of hBN and other materials.
In this work we report large area synthesis of hBN on Cu foil by chemical vapor deposition and its subsequent H2 etching to form highly directional triangular holes [2].Our system consist of single furnace with quartz tube as CVD chamber. Ammonia Borane was used as precursor kept away from growth zone during annealing to prevent early evaporation. During growth boat was moved closer to furnace to sublimate and evaporate precursor. As synthesized hBN was high quality and few layer demonstrated XPS, Auger, UV-IS and AFM analysis. After the growth precursor was moved away from furnace and hBN was subjected to etching. Different sets of experiment were carried out to study effect of temperature on etching mechanism. It was observed that at temperature < 9500C etching was isotropic visible only on grain boundaries and edges of crystal. But at higher temperature (≥9500C ) highly anisotropic etching was observed with triangular etched holes all over the crystal. Temperature dependent transition of isotropic to anisotropic etching can be explained from the fact that at higher temperature H2 solubility in Cu is increased many fold enabling H2 to move around the Cu and induce etching upon finding a defective hBN region. Controlled formation of triangular holes on hBN can serve as template for growing other 2D material like graphene for synthesis of inplane heterostructure. Variety of engineered 2D materials can be synthesized with desired electronic properties by choosing suitable combination of hBN and other materials.