【International Papers】2 in. Bulk β-Ga₂O₃ Single Crystals Grown by EFG Method with High Wafer-Scale Quality

      Researchers from the Nanjing University of Posts and Telecommunications have published a dissertation titled "2 in. Bulk β-Ga₂O₃ Single Crystals Grown by EFG Method with High Wafer-Scale Quality " in ACS Omega.

Abstract

      2 in. bulk β-Ga₂O₃ single crystals are successfully grown by the edge-defined film-fed growth method with a homemade furnace system. By considering the significance of wafer quality in future mass manufacture, a nine-point characterization method is developed to evaluate the full-scale quality of the processed 2 in. (100)-orientated β-Ga₂O₃ single-crystal wafers. Crystalline and structural characteristics were evaluated using X-ray diffraction and Raman spectroscopy, revealing decent crystalline quality with a mean full width at half-maximum value of 60.8 arcsec and homogeneous bonding structures. The statistical root-mean-square surface roughness, determined from nine scanning areas, was found to be only 0.196 nm, indicating superior surface quality. Linear optical properties and defect levels were further investigated using UV–visible spectrophotometry and photoluminescence spectroscopy. The high wafer-scale quality of the processed β-Ga₂O₃ wafers meets the requirements for homoepitaxial growth substrates in electronic and photonic devices with vertical configurations.

Figure 1. (a) Schematic diagram of the furnace for the EFG process; (b) growth stages and RF power profiles; (c) static temperature distribution of the furnace system during the steady-growth process, and (d) pictures of an initial bulk crystal and two processed 2 in. wafers

Figure 2. (a) Nine-point theta-2theta XRD patterns (the inset is the distribution map of nine mensurated points) and (b) nine-point rocking curves; (c) nine-point Raman spectra, and (d) S1 Raman spectrum with marked peaks.

Original link:https://doi.org/10.1021/acsomega.4c00405