  In this paper, 2-inch free-standing diamonds were prepared by using
heteroepitaxy on composite Ir/YSZ/Si (001) substrates. To release stress,
patterned templates were fabricated using laser etching after the initial
growth of 50-nm-diamond. Then, the subsequent growth was completed on a
patterned template. The full width at half maximum of the diamond (400) and
(311) X-ray rocking curves were 313.5 and 359.3 arcsecs, respectively. Strong
band-edge emission in the cathodoluminescence spectrum of the resulting diamond
revealed excellent crystalline quality. Furthermore, the 2D mapping of Raman
spectra was conducted on a $2 mm \times 2 mm$ area located at the center of the
2-inch sample with a thickness of $400 {\mu}m$. The result showed an average
peak width of $2.85 \pm 0.36 cm^{-1}$ and residual stress of $-0.03 \pm 0.37
GPa$. The dislocation density, determined by counting etching pits generated
from $ H_2/O_2$ plasma etching, was estimated to be around $2.2 \times 10^7
cm^{-2}$. These results evidence that the laser-patterned method can
effectively release stress during the growth of large-size diamonds, offering a
simpler and more cost-effective alternative to the traditional
photolithography-patterned scheme.
