Nitrides Seminar - Brian Romanczyk, Graduate Student Researcher
5/3/2017 12PM ESB 1001
The material properties of GaN are well suited for fabricating transistors used in mm-wave (30-300 GHz) power amplification. While most efforts have historically focused on HEMTs grown in the Ga-polar orientation, our work uses the N-polar orientation. The inverted polarization fields in N-polar GaN offer many advantages. In particular, the Deep Recess N-polar HEMT structure described in this work, wherein a thick GaN cap layer is added in the device access regions and recessed under the gate, is enabled by this inverted polarization. The GaN cap simultaneously mitigates DC-RF dispersion and decreases parasitic resistances, two factors which are required for high performance large signal device operation.
In this talk, the recent advances in our N-polar Deep Recess HEMT technology that have led to our demonstration of record-high large signal power density and efficiency at 94 GHz will be discussed.