Fabrication Of Ku Band High Power Internally-Matched Device

The internally matching of Ku band microwave power device is mainly researched. And the technological approach of Ku band GaAs microwave high power device is resolved. In the Ku band(14.0～14.5GHz),the internally matched 15W high power device is fabricated successfully.An internally matching GaAs power device is made up of chips, package, input internally matching circuit and output internally matching circuit. Namely, the active chips and the passive microwave matching components are packaged standardly to amplify the power in a certain microwave band.First of all, in the design of chip processes, the process of recess etching controls the recess thickness. And the gradient recess and the structure of gate closed to source are adopted, which improves the breakdown voltage effectively. In the process of device passivation, the ratio of He/N2 is adjusted to control the content of H. This method reduces the SiN film stress effectively. Through many experiments about the alloying condition, the optimized process of ohmic contact is confirmed. The 19.2mm gate-width and 0.35um gate-length GaAs power HFET has been fabricated. Then the impedance of HFET chip is matched. The LC matching circuit consists of bond wire inductance and high dielectric ceram capacitance. It transforms the impedance of chip. Then the impedance is matched to 50 ohm by using a quarter wave transformer. The power of two chips is combined through the power combiner. And the matching circuit is optimized by ADS. The matching components whose parameter value is got by optimizing are made. Because the chips and the matching components need to be packaged, the electricity and calorifics analysis is made about the package and the new structure of three steps is designed to meet the requirement of plane transmission in the high frequency of Ku band. Furthermore, the testing system is improved. The designed testing clamp has less wastage and its flatness is better. Finally, the chips and the matching components are assembled in the package by bonding and sintering. And the matching circuit is adjusted to make the chips demonstrate better performance. By debugging, the device with two chips demonstrates the saturation drain current(I_dss) of 300mA/mm, the transconductance(G_m) of 390mS/mm, the source-drain breakdown voltage(BV_sd) of 14V/5mA, output power more than 42dBm(15.8W) with more than 7dB power gain , more than 36% PAE and more than 90% co-efficiency in the band of 13.7～14.5GHz with V_ds=9V and P_in=35dBm. At 14.3 GHz, the output power 42.54 dBm (17.9W) and power gain 7.54 dB has been reached.