An extraction method of charge trapping site distribution in AlGaN layer in GaN HEMT

The density and distribution of electron traps in AlGaN layer of GaN HEMT have been characterized. Based on electron tunneling between 2DEG and trap sites, the distance and density can be extracted with frequency dependent capacitance and conductance responses. With parameter fitting to measured capacitance and conductance spectra, a trap density of N_bt = 10²¹ cm^-3eV^-1 has be extracted. With different gate voltage or measurement temperature, the trap distribution within the AlGaN layer can be extracted under the same frequency range. From measurement temperature dependency, a capture cross section σ₀ = 8 × 10^-10 cm² with an activation energy of 0.42 eV has been extracted.