Mikawa Yutaka - Academia.edu (original) (raw)

Mikawa Yutaka

Uploads

Papers by Mikawa Yutaka

Research paper thumbnail of Characterization of low-dislocation synthetic quartz grown on highly distorted seed by X-ray topography

Proceedings of the 1999 Joint Meeting of the European Frequency and Time Forum and the IEEE International Frequency Control Symposium (Cat. No.99CH36313)

In the present study, the feasibility to grow a dislocation-free synthetic quartz with large Z-re... more In the present study, the feasibility to grow a dislocation-free synthetic quartz with large Z-region from a seed containing high density of dislocation is reported. For such purpose, a seed with new geometric design was prepared. A seed long in Y-direction and containing V-shaped cuts with cutting angle of 90" made on Z-face {OOOl was prepared and grown in the hydrothermal process. As a result, new growth regions usually not found in the conventional Yand Z-bars synthetic quartz crystals have been imaged by the X-ray topography. The new growth region grown from the V-shaped cut was composed with two sub-regions of distinct textures. Due to their high growth velocity perpendicularly to cut faces, they disappeared and were replaced by the so-called Z-region. However, these newly grown sub-reyions played an important role to change the direction of dislocation propagation present in the seed trapping them and minimizing their propagation into the grown Z-region.

Research paper thumbnail of Electronic and optical characteristics of an m-plane freestanding GaN substrate grown by hydride vapor phase epitaxy on a GaN seed crystal synthesized by the ammonothermal method using an acidic mineralizer

Research paper thumbnail of Characterization of low-dislocation synthetic quartz grown on highly distorted seed by X-ray topography

Proceedings of the 1999 Joint Meeting of the European Frequency and Time Forum and the IEEE International Frequency Control Symposium (Cat. No.99CH36313)

In the present study, the feasibility to grow a dislocation-free synthetic quartz with large Z-re... more In the present study, the feasibility to grow a dislocation-free synthetic quartz with large Z-region from a seed containing high density of dislocation is reported. For such purpose, a seed with new geometric design was prepared. A seed long in Y-direction and containing V-shaped cuts with cutting angle of 90" made on Z-face {OOOl was prepared and grown in the hydrothermal process. As a result, new growth regions usually not found in the conventional Yand Z-bars synthetic quartz crystals have been imaged by the X-ray topography. The new growth region grown from the V-shaped cut was composed with two sub-regions of distinct textures. Due to their high growth velocity perpendicularly to cut faces, they disappeared and were replaced by the so-called Z-region. However, these newly grown sub-reyions played an important role to change the direction of dislocation propagation present in the seed trapping them and minimizing their propagation into the grown Z-region.

Research paper thumbnail of Electronic and optical characteristics of an m-plane freestanding GaN substrate grown by hydride vapor phase epitaxy on a GaN seed crystal synthesized by the ammonothermal method using an acidic mineralizer

Log In