0.25 mu m gate inverted HEMTs for an ultra-high speed DCFL dynamic frequency divider

A 0.25- mu m-gate inverted HEMT (I-HEMT) was fabricated using a conventional recess gate process. The recess etching was performed by RIBE (reactive-ion-beam etching). A minimum propagation delay time of 10 ps/gate at a power dissipation of 43.3 mW was measured for a directly coupled FET logic (DCFL) ring oscillator. A novel 1/8 dynamic frequency divider was fabricated using the 0.25- mu m-gate I-HEMTs. The maximum operating frequency for the dynamic divider was 26.5 GHz at a power dissipation of 0.573 W. The frequency is the upper limit of the measurement system used. This is the best result ever reported for DCFL circuits.<>