High Performance GaN HEMTs on 3-inch SI-SiC Substrates
K.S. Boutros, M. Regan, P. Rowell, D. Gotthold,* and B. Brar
Rockwell Scientific Company
Camino Dos Rios,
805-373-41-4; fax: 805-373-4680; e-mail: firstname.lastname@example.org
Keywords: GaN HEMTs, wafger scaling, 3-inch SI-SiC substrates, mmWave power MMICs
Gallium Nitride (GaN) HEMTs are the focus of intense research and development due to their potential for the realization of MMIC power amplifiers (PAs) with high gain and record levels of power delivery . Much of the work in GaN HEMT development has been concentrated on performance demonstration of 2” SiC and Sapphire substrates. Multiple groups have demonstrated GaN HEMTs delivering record power performance at microwave and mmWave frequencies [2,3]. Recently, there has also been major progress in the improvement of uniformity and reproducibility of GaN HEMT 2” epitaxial wafers on both substrates, available through multiple electronic thermal conductivity and lower dislocations in GaN film, which has a large impact on the performance of GaN power devices. However, until recntly, only 2” SI-SiC was available for GaN HEMT development. Scaling of the GaN technology to 3” will result in doubling the number of MMIC die per wafer. This will be instrumental in the reduction of the overall cost of GaN-based MMICs, and ultimately, in the introduction of this technology into commercial and military systems.
This paper presents the successful scaling of GaN HEMT fabrication process to 3” semi-insulation (SI) SiC substrates using 0.18 mm gate-length technology. A base-line GaN fabrication process, suitable for mmWave applications, is demonstrated on 3” GaN epi-wafers. GaN HEMTs were fabricated with high yield and uniformity. Device performance on 3” substrates was similar to what can be achieved on material grown on 2” SiC. The basic device fabrication technology, along with DC and RF characteristics of GaN HEMTs fabricated with 0.18 mm technology are presented.