CMOS Compatible High-voltage GaN-on-Silicon HEMT reaches 300mm
An GaN wafer epi-foundry with headquarters located at Suzhou Industrial Park, China, Enkris Semiconductor announced that it has demonstrated a series of high quality 300mm GaN-on-Si HEMT epiwafers of excellent thickness uniformity and low wafer bow for 200V, 650V and 1200V power applications, paving the way for device processing using more sophisticated 300mm CMOS-compatible lines.
The advances in the GaN epitaxy on large size Si substrates have enabled GaN-on-Si power devices with impressive performance and reliability by combing the full advantage of both the remarkable properties of GaN and of production in a CMOS compatible processing line. Nowadays, commercial GaN power devices based on GaN-on-Si HEMT technology platform have gained a tremendous momentum to enter a wide range of applications such as consumer electronics, Industrial electronics, Data Centre, Energy, Automotive & Mobility etc. Driven by cost reduction and more sophisticated integrated circuits design, the industry is moving towards larger wafer size.
Following its successful launch of commercial 200mm GaN-on-Si HV HEMT epiwafers in 2014, Enkris Semiconductor have successfully transferred its AlGaN/GaN HEMT epitaxy process to 300mm Si substrates, while maintaining the excellent thickness uniformity and low wafer bow within 50µm. The vertical voltage breakdown measurements suggest the wafers are suitable for
200V, 650V and 1200V power applications (Figure 1).
Figure 1: The thickness map and vertical breakdown voltage (leakage current = 1uA/mm2 @ RT) of a series of Enkris 300mm GaN-on-Si HEMT epiwafers targeting 200V, 650V and 1200V power applications, respectively.
The 300mm GaN-on-Si HEMT epitaxial layer structure adopted to solve the key issues of wafer cracking/bow and high crystalline defects is shown in figure 2(a). The growth starts with an AlN nucleation layer, followed by a strain relief stack, GaN channel, AlGaN barrier and GaN cap. The narrow XRD AlN(002) peak and a good uniformity of FWHM, as shown in Figure 2(b), indicate a high crystalline quality across the whole 300mm wafer.
Figure 2: (a) The schematic structure of Enkris 300mm GaN-on-Si HEMT epiwafers. (b) The map of XRD AlN(002) FWHM, giving an average FWHM value of 743 arcsec and a STD of 2%.
Figure 3 shows the Al composition in the AlGaN barrier and the 2DEG carrier concentration measured at 9 positions from wafer centre to wafer edge. The measurements give an average value of 19.9% and a std of 0.68% of Al composition in the AlGaN barrier (figure 3a), suggesting a uniform 2DEG electrical characteristics. This has been confirmed by the CV measurements, revealing an average electron concentration of 7.2E12 cm-2 with a std <2% (figure 3b).
Figure 3: The Al composition and 2DEG electron concentration measured from Enkris AlGaN/GaN HEMT epiwafer grown on 300mm Si substrates.
“Thanks to our optimised AlN nucleation layer, we are able to produce crack-free GaN-based HEMT epiwafers that meet the leakage current requirements on large size Si substrates up to 300mm”, said Dr Kai Cheng, CEO of Enkris. “Despite the challenges in epitaxy process, strain management and defect control when moving to 300mm wafer size, we have achieved excellent structural quality and electrical properties in the AlGaN/GaN HEMT structures. This will certainly encourage the development of high-power integrated circuits to yield system-on-chip and further reduce the cost of GaN power devices.”
Enkris Semiconductor was founded in 2012 as a pure epi-foundry of GaN wafers. We provide high quality GaN epiwafers to our customers for power electronics, RF, MicroLED and UVC applications. Our product range includes GaN-on-SiC, GaN-on-sapphire, GaN-on-GaN and GaN-on-Si with wafer size up to 300mm. We can also grow customized structures for our customers to meet their specific requirements.
Address: Enkris Semiconductor, Inc.NW-20-517, 99 Jinji Avenue Suzhou Industrial Park, 215123, China
Phone: +86 (512)62706800