Effect of Polarization Coulomb Field Scattering on Parasitic Source Access Resistance and Extrinsic Transconductance in AlGaN/GaN Heterostructure FETs

Effect of Different Gate Lengths on Polarization Coulomb Field Scattering Potential in AlGaN/GaN Heterostructure Field-Effect Transistors

“…The polarization charges under the free-contact region is ρ 0 , therefore the additional charges can be obtained by 36–38,41 The additional polarization charges Δσ 1 is under the gate region. Based on the obtained Δσ 1 , the PCF scattering potential can be written as 31,37,38,50 If the for the electrons under the gate region is chosen, as shown in Fig. 5(d), Ψ( x, y, z ) under the gate region is used.…”

“…Based on the obtained Δσ 2 , the PCF scattering potential can be expressed by 31,37,38,50 Here L GS and L GD refer to the gate-source spacing and gate-drain spacing, respectively.…”

“…With the obtained Ψ( x , y , z ) and V ( x , y , z ), the scattering matrix element is given by 31,37,38,50 where q x , q y refer to the components of the wave vector q in the x -direction and y -direction, respectively. The change in q during a scattering process is related to the scattering angle θ between initial state k and final state k ′ by q  = |2(2 m * ℏ −2 E ) 1/2 sin ( θ /2)|.…”

“…Then the energy dependent scattering rate for the PCF scattering can be obtained 31,37,38,50 where ћ is the Planck constant. The screening function S ( q , T e ) is 31,37,38,50 Here the form factor F ( q ) is 31,37,38,50 …”

“…The polarizability function Π ( q , T e , E ) is 31,37,38,50 In this equation, Θ( x ) is the usual step function, k F  = (2 πn 2D ) 1/2 is the Fermi wave vector, T e is the electron temperature, E F is the Fermi energy, and E is the energy.…”