Study On Emulation And Process Of Si-based High Frequency Field-Effect-Transistor

With the highly frequency components are widely used in the field of electronicinformation technology, a new generation of microwave and millimeter wave devices whichrepresented by GaAs-HEMT have became indispensable components in the field of highlyfrequency satellite communications, radio astronomy, electronic warfare, etc. During recentyears, the highly frequency GFET have gradually draw the wide attention of researchers bothat home and abroad due to the zero forbidden band feature of graphene. Silicon, which mostwidely used in semiconductor materials, the mature technology and excellent features makethe devices embraced the low cost, wide application. The paper focuses on the DCcharacteristics and processing technology of Si-based GaAs-HEMT and Si-GFET.(1) TCAD tool was used to emulate the DC characteristics of GaAs-HEMT: i.With theincreases of thickness of the GaAs-HEMT’s barrier layer, the threshold voltage graduallyincreases and the transconductance of source and drain gradually converges of the barrierlayer’s thickness reduction; ii.GaAs HEMT’s transconductance increases with the decreasesof gate-length and the threshold voltage moves into positive voltage direction with theincreases of the gate-length; iii.The doped barrier layer will lead to an increase in the gateleakage current while the device with double conductive channel; iv.GaAs HEMT’stemperature coefficient associated with the grid voltage, the coefficient in10-6orders ofmagnitude when the grid voltage is0V.(2) The Si-based GaAs HEMT structure was designed and processed: i.The superlatticetechnology was used to optimize the Si-based GaAs film material, and the scanning electronicmicroscope (SEM) was used to observe the defect density of the optimized film materialwhich is about106orders of magnitude and the surface roughness is5.21nm at10×10um2range of thin film by the using of the atomic force microscope (AFM), at the same time, thefilm optimization can be clearly observed by means of transmission electron microscope (TEM) and X-ray diffraction (XRD); ii.With the different characteristics of corrosion rates ofthe citric acid/hydrogen peroxide against GaAs and AlGaAs material, the highestGaAs/AlGaAs selective corrosion is about3.5when the proportion of hydrogen and peroxideis3:1; iii.The Si-based GaAs HEMT structure was produced by using surface microelectronictechnology.(3) The Si-based GFET was designed and processed by technology of reactive ionetching (RIE), ohmic contact process, schottky contact process, metal stripping process andatomic layer deposition (ALD) process,etc..(4) The basic electrical characteristics of Si-based highly frequency field effect transistorstructure were tested: i.The highest source-drain current of is about7mA, the thresholdvoltage is about-2.8V after DC testing of Si-based GaAs HEMT structure, and analysis theSi-based GaAs-HEMT process feasibility of the test results; ii.The device channel resistanceis about1600after testing the Si-GFET DC characteristics.The article combines the highly frequency characteristic of GaAs-HEMT withmechanical characteristic of silicon material, and innovative proposed the Si-based GaAsHEMT structure, which provide a technology basis for extending the application scope ofGaAs HEMT. At the same time, the processing craft of Si-based GFET is achieved, and agood performance of Si-GFET structure is obtained.