No abstract

No abstract

No abstract

We have demonstrated state-of-the-art characteristics of AlGaN/GaN-on-Si heterojunction field effect transistors (HFETs) employing dual field plates. Both gate and drain field plate lengths were optimized in order to maximize the breakdown voltage. Great care was taken not only to optimize the field plate lengths but also to develop processing technologies such as mesa-first prepassivation, a recessed ohmic contact, and a sloped gate. A breakdown voltage of 1590 V with a specific on-resistance of 1.86 m cm 2 was achieved for the gate-to-drain distance of 15 m in which the gate and drain field plate lengths were 2 and 1 m, respectively. #

Recently, Young's equation, the Wenzel equation, and the Cassie-Baxter equation have been widely used with active research on superhydrophobic surfaces. However, experiments showed that the Wenzel equation and the Cassie-Baxter equation were not derived correctly. They should be reviewed on a firm physical ground. In this study, these equations are re-derived from a thermodynamic point of view by employing energy minimization and variational approach. The derivations provide a deeper understanding of these equations and the behavior of a contact angle. Also, in applying these equations, the limitations and considerations are discussed. It is expected that this study will provide a theoretical basis for the careful use of these equations on rough or chemically heterogeneous surfaces.