Demonstration of Constant 8 W/mm Power Density at 10, 30, and 94 GHz in State-of-the-Art Millimeter-Wave N-Polar GaN MISHEMTs

Effects of alloy composition and Si-doping on vacancy defect formation in (InxGa1–x)2O3 thin films

“…Similar to the effect of Si doping, the presence of ionized donors would as well lead to changes in the electric fields landscape resulting in restrained positron localization at the bottom AlGaN/GaN interface. The experimental and theoretical positron annihilation spectra for the N-polar GaN/AlGaN/GaN heterostructures demonstrate positron annihilation at the aforementioned interface region which contains neutral V N in the sheet concentration of approximately ∼ 10 14 cm −2 , comparable to the sheet carrier concentration at the top interface of HEMTs [134]. Previously N deficiency has been observed indirectly through the increase in the number of V N in V In − nV N complexes at InN/GaN interfaces [39,146,147].…”

“…For GaN, Ga-polar growth direction is traditionally preferred over N-polar due to higher chemical stability and smoother surface morphology. However, N-polar GaN notably facilitates the electron transport properties and the performance of GaN/AlGaN/GaN HEMTs [132,134,135]. The surface polarity also affects oxygen incorporation, typically with higher oxygen concentration on the N-face [136,137].…”

High Performance and Highly Robust AlN/GaN HEMTs for Millimeter-Wave Operation

“…Fig. 11(a) shows that these devices are favorably comparable to the Ga-Polar HEMTs state-of-the-art both in Q-band [1]- [8] and W-band as shown in Fig. 11(b) [9]- [15].…”

“…That is why, achieving both high PAE and output power density (P OUT ) in the millimeter-wave (mmW) range represents currently one of the key goal for the GaN technology. High Electron Mobility Transistors (HEMT) on SiC have already demonstrated attractive efficiencies up to Ka-Band [1]- [5] but limited data have been reported so far in the Q-Band [6]- [8] and above [9]- [15]. To obtain very high frequency performance, it is necessary to shrink the device dimensions and wisely optimize the epilayer stack, especially the barrier thickness.…”

An Improved Large Signal Model for 0.1 μm AlGaN/GaN High Electron Mobility Transistors (HEMTs) Process and Its Applications in Practical Monolithic Microwave Integrated Circuit (MMIC) Design in W band

“…With the rapid development of process, the feature size of GaN HEMTs have been shrinking to less than 0.1 µm. GaN HEMTs with good performance for application in W band have been reported [ 2 , 3 , 4 , 5 ]. Also, over the past few years, several GaN HEMT based monolithic microwave integrated circuits (MMICs) up to W-band have been developed, due to their applications in high speed wireless communications or radar systems [ 6 ].…”