Cryogenic GaN/AlGaN HEMT ICs and fabrication probability of monolithic sensor of super- and semiconductor devices

GaN/AlGaN HEMTs are usually used as high speed circuit elements and fabricated onto silicon or sapphire substrate. Since they also show good cryogenic properties even in low power condition (~1 μW/1 HEMT), we designed and fabricated some GaN/AlGaN HEMT integrated circuits. By using source follower with sample-and-hold which is one of the ICs, performance as source follower and sample-and-hold is confirmed. Now we have investigated how to fabricate superconductor devices onto the substrate which GaN/AlGaN HEMT devices are already fabricated. When we realize this technique, some new monolitic instruments with super- and semiconductor devices may be made come true.