InGaAs HEMTs with T-gate electrodes fabricated using HMDS SiN mold

We report a method using SiN molds to controlling the shape of T-gate electrodes. The SiN molds were constructed of multilayer SiN films with different etching properties. The SiN was deposited by plasma-enhanced chemical vapor deposition using hexamethyldisilazane (HMDS) vapor. The SiN molds were used to fabricate T-gate electrodes for InGaAs high electron mobility transistors (HEMTs). Two types of HEMTs were fabricated using the molds with different SiN layer structures. The gate delay analysis of the HEMTs showed that the difference in the parasitic gate delay reflects the shape of the T-gate electrodes.