In this study, we fabricated AlGaN/GaN-on-Si high electron mobility transistors (HEMTs) for high voltage switching applications where both the field plate length and the gate-to-drain distance were varied for structural optimization. A tapered gate was fabricated in conjunction with the field plate in order to effectively suppress the high electric field at the gate edge. Regardless of the gate-to-drain distance, which was varied from 7 to 20 µm, the highest breakdown voltage was obtained with a short field plate length (i.e., 2 -3 µm), and the breakdown voltage monotonically decreased with increasing field plate length. A breakdown voltage of 1200 V with an on-resistance of 3.7 mΩ·cm 2 was achieved using a gate-to-drain distance of 20 µm and a field plate length of 3 µm.
Integrated antennas operating at millimeter-wave (mm-wave) frequency have been implemented on a benzocyclobutene (BCB)-based system-onpackage (SOP) substrate. A novel BCB-based SOP substrate with a Si bump and a Si cavity was proposed to increase the BCB thickness, thus enhancing the gain of the microstrip patch array antenna and reducing the transfer loss of the transmission line. The mechanical issues of adhesion and stress of BCB are studied. The adhesion between gold and BCB was improved significantly by the insertion of a layer of Si oxide (SiO 2 ) by plasma-enhanced chemical vapor deposition (PECVD). SiO 2 can also reduce the wafer bow by stress compensation. Wafer bow of whole structure was decreased from 79.3 to 55.2 m by the insertion of a 1-m-thick SiO 2 layer. A series-fed 1 Â 8 linear array antenna is impedance matched well at 77 GHz. The process flow including BCB chemical mechanical polishing (CMP) was described. The proposed SOP substrate can be a candidate for overcoming the constraint of BCB thickness. #
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.