Infrared Phototube for Microwave Modulated Laser Radar Applications

Not Available High power microwave and millimeter-wave amplifiers for wireless communication base-stations, wireless local area networks, digital radio, and airborne or space-based applications like phased array radar, satellites communications are increasingly utilizing solid state power amplifiers. Nitride based wide bandgap semiconductors have demonstrated microwave power densities substantially higher than conventional structures such as GaAs MESFETs and HEMTs. The AlGaN-GaN HEMT is the most attractive since high voltage, high current and low on-resistance can be simultaneously achieved, resulting in high power-high efficiency operation. Loss in large signal rf performance, both in power and PAE is one of the most important problem in current state of the art AlGaN-GaN HEMTs. In this program, WiTech proposes to address this problem by developing the Silicon Nitride insulating Gate HEMTs (SiNG-HEMT) in the AlGaN-GaN material system. As explained in the proposal, the SiN insulator will alleviate the trapping effect in AlGaN-GaN HEMTs. This will enable the GaN HEMT technology that achieves power densities ~ 10 times and power added efficiencies higher than existing GaAs MESFET and pHEMT microwave technologies. In phase I, WiTech shall fabricate 0.6 um gate length SiNG-HEMTs operating at a high power density (~ 3-5 W/mm), high efficiency (> 40 %) at C band. The SiNG-HEMT will be compared to a baseline AlGaN-GaN HEMT to quantify the effect of the SiN insulating gate on the device performance. Phase II goals would be to target higher power densities (~ 5-7 W/mm) as well as higher efficiencies (~ 60-70 %), demonstration of enhancement mode SiNG-HEMTs and increased reliability.