Trap Analysis Of Composite 2d-3d Channel In Algan/Gan/Graded-Algan:Si/Gan:C Multi-Heterostructure At Different Temperatures*

The graded AlGaN:Si back barrier can form the majority of three-dimensional electron gases (3DEGs) at the GaN/graded AlGaN:Si heterostructure and create a composite two-dimensional (2D)-three-dimensional (3D) channel in AlGaN/GaN/graded-AlGaN:Si/GaN:C heterostructure (DH:Si/C). Frequency-dependent capacitances and conductance are measured to investigate the characteristics of the multi-temperature trap states of in DH:Si/C and AlGaN/GaN/GaN:C heterostructure (SH:C). There are fast, medium, and slow trap states in DH:Si/C, while only medium trap states exist in SH:C. The time constant/trap density for medium trap state in SH:C heterostructure are (11 mu s-17.7 mu s)/(1.1 x 10(13)cm(-2)center dot eV(-1)-3.9x 10(13)cm(-2)center dot eV(-1)) and (8.7 mu s-14.1 mu s)/(0.7x 10(13)cm(-2)center dot eV(-1)-1.9x 10(13)cm(-2)center dot eV(-1)) at 300 K and 500 K respectively. The time constant/trap density for fast, medium, and slow trap states in DH:Si/C heterostructure are (4.2 mu s-7.7 mu s)/(1.5x 10(13)cm(-2)center dot eV(-1)-3.2x 10(13)cm(-2)center dot eV(-1)), (6.8 mu s-11.8 mu s)/(0.8x 10(13)cm(-2)center dot eV(-1)-2.8x 10(13)cm(-2)center dot eV(-1)), (30.1 mu s-151 mu s)/(7.5x 10(12)cm(-2)center dot eV(-1)-7.8x 10(12)cm(-2)center dot eV(-1)) at 300 K and (3.5 mu s-6.5 mu s)/(0.9x 10(13)cm(-2)center dot eV(-1)-1.8x 10(13)cm(-2)center dot eV(-1)), (4.9 mu s-9.4 mu s)/(0.6x 10(13)cm(-2)center dot eV(-1)-1.7x 10(13)cm(-2)center dot eV(-1)), (20.6 mu s-61.9 mu s)/(3.2x 10(12)cm(-2)center dot eV(-1)-3.5x 10(12)cm(-2)center dot eV(-1)) at 500 K, respectively. The DH:Si/C structure can effectively reduce the density of medium trap states compared with SH:C structure.