New manufacturing shortcut could speed up gallium oxide chip production
Researchers have developed a faster, cheaper way to grow high-quality gallium oxide layers for next-generation power semiconductors, cutting substrate preparation time from one hour to one minute. The advance could reduce production costs and accelerate commercialization of gallium oxide devices, which promise superior efficiency in electric vehicles and renewable energy systems.
Originaltitel: High crystalline quality homoepitaxial Si-doped <em>β</em>-Ga<sub>2</sub>O<sub>3</sub>(010) layers with reduced structural anisotropy grown by hot-wall MOCVD
<p>A new growth approach, based on the hot-wall metalorganic chemical vapor deposition concept, is developed for high-quality homoepitaxial growth of Si-doped single-crystalline beta-Ga2O3 layers on (010)-oriented native substrates. Substrate annealing in argon atmosphere for 1 min at temperatures below 600 degrees C is proposed for the formation of epi-ready surfaces as a cost-effective alternative to the traditionally employed annealing process in oxygen-containing atmosphere with a time duration of 1 h at about 1000 degrees C. It is shown that the on-axis rocking curve widths exhibit anisotropic dependence on the azimuth angle with minima for in-plane direction parallel to the [001] and maximum for the [100] for both substrate and layer. The homoepitaxial layers are demonstrated to have excellent structural properties with a beta-Ga2O3(020) rocking curve full-widths at half-maximum as low as 11 arc sec, which is lower than the corresponding one for the substrates (19 arc sec), even for highly Si-doped (low 1019 cm -3 range) layers. Furthermore, the structural anisotropy in the layer is substantially reduced with respect to the substrate. Very smooth surface morphology of the epilayers with a root mean square roughness value of 0.6 nm over a 5 x 5 mu m(2) area is achieved along with a high electron mobility of 69 cm 2 V -1 s -1 at a free carrier concentration n = 1.9 x 10(19) cm -3. These values compare well with state-of-the-art parameters reported in the literature for beta-Ga2O3(010) homoepitaxial layers with respective Si doping levels. Thermal conductivity of 17.4 Wm(-1)K(-1) is determined along the [010] direction for the homoepitaxial layers at 300 K, which approaches the respective value of bulk crystal (20.6 Wm(-1)K(-1)). This result is explained by a weak boundary effect and a low dislocation density in the homoepitaxial layers.</p>