The enhancement mode AlGaN/GaN high electron mobility transistor based on charge storage

In this paper, we sums up our resent progress on the enhancement-mode (E-mode) AlGaN/GaN high electron mobility transistors (HEMTs) which are based on charge storage, including the split floating gates (FGs) HEMT and the one with oxide-SiN-oxide (ONO) gate dielectrics stack. For the FGs HEMT, the V
_th
variation with the polarization charge density, the density of two dimensional electron gas, the tunnel dielectric thickness, the blocking dielectric thickness, the length and isolating spacing of FGs are presented. The reliability of the FGs HEMT are also revealed. For the HEMT with ONO gate dielectrics stack, the E-mode is realized by negative charge storage within the SiN trap layer. The V
_th
variation with the programming condition and the thickness of the dielectrics are presented. Under proper programming voltage and time, the V
_th
can be increased to more than 2V. Moreover, it is found that the breakdown voltage of such HEMT can be adjusted by varying the gate dielectric stacks.