GaN/AlGaN on silicon MBE
Jean-Luc Ledys, Picogiga's chief operating officer, comments: "Today, most AlGaN/GaN HEMTs are offered on sapphire or silicon carbide (SiC) substrates, and these approaches are hampered by poor thermal conductivity, high procurement costs and lack of availability for large-diameter wafers. Combining the performance benefits of GaN with the cost advantages of large-area silicon will help ensure broad commercial availability of GaN-based substrates."
GaN is a very promising material for high-power, high-frequency products. One of the major challenges associated with GaN technology is growing the material - choice of substrate is intrinsically linked to this. Silicon has many desirable properties as a substrate material (low cost, high quality and ready supply). Unfortunately it is not easy to grow compound semiconductor layers on silicon because of their different physical properties. Picogiga claims that its MBE deposition process overcomes these challenges.
Picogiga's process can also put AlGaN on silicon. HEMT devices based on this structure can have power levels exceeding 6W/mm at 2GHz, can handle operating frequencies in the ranging 5-10GHz with a transconductance (Gm) of 350mS/mm and can sustain voltages up to 60-70V.
Picogiga believes that its AlGaN/GaN product family is ideally suited for 3G base-station RF power amplifier, as well as K-band radar applications. The structures are offered in 50mm, 75mm and 100mm wafer sizes, available now.
