In order to grow large-size AlN single crystals, countries around the world have made long-term unremitting efforts in crystal growing methods and processes in the past 50 years, but the progress is very slow. The physical vapor transport (PVT) is recognized as the only method for growing large bulk AlN single crystals, and this method is also an approach for growing large-size bulk SiC single crystals. The fundamental research on the growth of AlN and SiC single crystals both started in the 1970s, but tremendous progress on the SiC single crystals has been achieved. At present, 8-inch (200mm) diameter SiC wafers are being in mass production by leading companies. Nevertheless, research institutions and enterprises worldwide capable of growing 1-inch (25.4 mm) diameter AlN single crystals are extremely limited nowadays. Huge challenges are posed to the hot zone design, control system and equipment for the AlN single crystal growth due to the high growth temperature and stringent growth conditions. Therefore, The AlN single crystal and AlN single crystal growing equipment have been listed as key strategy material and equipment in “Made in China 2025” unveiled by the State Council and the Ministry of Industry and Information Technology (MIIT) of the People's Republic of China......
Invited by the committee of the international conference on Light-Emitting Devices and Their Industrial Applications (LEDIA-2019), Ultratrend Technologies Co., Ltd. officially launched world-first Φ60 mm AlN single crystalline wafers on April 24 at Pacifico Yokohama, Japan. LEDIA-2019 was held on 23-25 April and chaired by Nobel Laureate Prof. Hiroshi Amano. The launched wafers showed world-leading performance revealed by Raman spectroscopy and optical transmission spectra. The Raman spectroscopy exhibits an E2 (high) linewidth at half maximum of 2.85cm-1，and the entire wafers exhibit excellent UV transparency with the absorption coefficient of 14-21cm-1 in the UV range of 260-280nm. The relevant results were published in the famous academic journal Physica Status Solidi A, and chosen as the cover of this journal as well. This achievement means that Ultratrend Technologies Co., Ltd. has made an important breakthrough on this key strategic ultra-wide bandgap semiconductor material. Before this milestone, the largest size of reported AlN single crystalline wafers is 50.8 mm, and suck kind of wafers can only be fabricated with very limited volume ......
Traditional semiconductor materials such as silicon substrate can no longer meet the development requirements of current electronic devices. As a typical representative of the ultra-wide band-gap semiconductor materials, AlN has excellent physical and chemical properties such as ultra-wide band-gap, high thermal conductivity, high breakdown field strength, high electron mobility, corrosion resistance, and radiation resistance, especially suitable for manufacturing radio frequency communication devices, optoelectronic devices, power electronic devices and the like. It is the best substrate for ultraviolet LED, ultraviolet detector, ultraviolet laser, high power/high-frequency electronic devices and widely used in environmental protection, electronics, wireless communication, printing, biology, medical treatment, military and other fields, such as ultraviolet purification/sterilization (sewage treatment, drinking water disinfection, air sterilization, surface sterilization, deodorization, etc.), ultraviolet curing, ultraviolet catalysis, 5G wireless communication SAW/BAW, and other devices, anti-counterfeit detection, high-density storage, medical phototherapy, drug research and development, and secret communication, ultraviolet space detection and other fields.......
The growth temperature of AlN single crystals by the PVT method usually is as high as 2000ºC – 2300ºC in a closed environment and the crystal growth period is also very long, which pose extreme challenges to the stability of the temperature field and the accuracy of the control system. It is very difficult and expensive to tune process parameters through actual experiments to obtain limited experimental data due to the high growth temperature and harsh growth conditions, or even it is not feasible. Therefore, it has become an indispensable tool to analyze and optimize the AlN crystal growth process by means of numerical modeling and simulation.......