Rapid progress in multimedia communication handling a huge volume of data requires high-capacity in communication systems. Optical-fiber communication systems and millimeter-wave radio communication systems will play decisive roles, and essential high-speed digital ICs and MMICs will be the key devices in these systems. The InP-based heterostructure electron devices, such as HEMTs and HBTs, are thought to be the most promising candidates for these applications. To date, ultimate high f/sub T/ and f/sub max/ were well demonstrated using HEMTs based on InP. Consequently, much effort is being devoted to millimeter-wave, baseband, and digital applications. This paper reviews fabrication technologies our laboratory has developed for making 0.1-/spl mu/m-gate InP-based HEMTs to realize high-performance ICs.