In the typical mobile communication band of more than 2GHz, the RF signal loss through the Cds and Rs becomes significant.
ΦB AlGaN GaN Ec ∆Ec EF d σcomp AlGaAs donor σB +ve GaAs buffer layer 2 DEG σsurf AlGaAs spacer AlGaN/GaN HEMT AlGaAs/GaAs HEMTġ6 HEMT Applications A Monolithic HEMT Passive Switch for Phased- Array Applications High Power and High Efficiency GaN-HEMT for Microwave Communication Applications Highly efficient high power InP HEMT amplifiers for high frequency applications Highly Uniform InAlAs–InGaAs HEMT Technology for High-Speed Optical Communication System ICsġ7 A Monolithic HEMT Passive Switch for Phased- Array ApplicationsĪ 0.2 x 200 ,um2 HEMT device is used as a series passive FET switchġ8 High Power and High Efficiency GaN-HEMT for Microwave Communication Applications Lower noise Higher cutoff frequency Higher gain Operating voltage below 3 V Gate footprint, cross-sectional area and width controls the frequency response Gate drain spacing as well as gate footprint determines the breakdown voltage Geometry of the device also plays a role Thickness of the Barrier Layer Al composition of the barrier layer Nucleation and Buffer layer Substrate for epitaxial growthġ1 Design Rules For GaN/AlGaN HEMTs: Fabrication Perspective Highly doped layer with grand gap Non-doped layer with small gapġ0 Design Rules For GaN/AlGaN HEMTs: Materials Perspective Conduction band edge EC and Fermi level EF determine the electron density in the 2DEG Source:ĩ Heterojunction Heterojunction: 2 layers HEMTs utilize heterojunction between two semiconducting materials to confine electrons to a triangular quantum well. Acceptable thermal conductivity.ĪlGaN/GaN HEMTs transistor don’t need doping to obtain a high electron density. Most used material, cheap, good quality commercial wafers. switch, amplifiers, oscillators To satisfy the growing demands of High Power High Speed High Efficiency communications Conventional HEMTs use a AlGaAs/GaAs AlGaN/GaNĥ Gallium Nitrate High electron density(Polarization effects)Īdequate for high power amplifiers High Breakdown voltage Large heat capacity Necessary to growth in a wafer of another material Molecular Beam Epitaxy Metal Organic Vapor Beam EpitaxyĦ Substrate Material Sapphire Silicon Carbide Silicon Presented by: Date: Sujana Korrapati, Sai Divya AnneĢ Outline Introduction GaN HEMT structure and operation principlesĭesign rules for AlGaN/GaN HEMT InP HEMT Comparison of GaN HEMT with GaAs HEMT Applications in Technology Summaryģ Introduction Transistors are used in electronic devicesĮ.g. We will discuss different types of HEMTs and their Applications.
Abstract: HEMT is a field effect transistor incorporating a junction between two materials with different band gaps as the channel.
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