Kopin Makes Massive Moves In GaN HEMT Technology
The firm says its process has achieved record mobility and sheet resistance in indium gallium nitride channel HEMTs grown on silicon carbide for next generation high-performance electronic devices
Kopin has announced that it has obtained record results from GaN-based high electron mobility transistor (HEMT) materials.
The advanced GaN-based materials developed at Kopin are important for improving performance of next-generation power amplifiers and power switching converters.
The research, which has recently been published in Applied Physics Letters, describes the use of InGaN as the conducting layer in HEMT structures grown on sapphire and SiC substrates. The use of an InGaN channel layer, instead of GaN has the benefit of providing a back-channel barrier for better electron confinement, which is important for deep sub-micron gate length devices to achieve ultra-high-frequency operation.
However, obtaining good InGaN channel HEMT materials is challenging since InGaN layers can become very rough during growth. Using proprietary MOCVD growth processes, Kopin scientists demonstrated a high electron mobility of 1290 cm2/V.s and a low sheet resistance of 240 Ω / square. Kopin says this is about 30 % lower than the previous best published result for device structures employing an InGaN channel.
John C.C. Fan, Kopin’s President and CEO, comments, “GaN-based devices are becoming increasingly important over a broad range of new applications requiring high-frequency, high-voltage, high-power, and/or high-temperature operation. With our rich and strong technical expertise in heteroepitaxy and III-V transistor wafers, we have been working on GaN-based transistor structures for electronic devices during the past few years. I am delighted that we are making rapid advances in this new class of materials and devices, maintaining and extending our leadership in III-V transistor wafers."
Further details of this work have been published in the paper, " InGaN channel high electron mobility transistor structures grown by metal organic chemical vapor deposition", by O. Laboutin et al, Applied Physics Letters, 100, 121909 (2012), published online on 23 March 2012.