Electron Mobility in Surface- and Buried-Channel Flatband In0.53Ga0.47As MOSFETs With ALD Al2O3 Gate Dielectric

Abstract

In this letter, we investigate the scaling potential of flatband III-V MOSFETs by comparing the mobility of surface- and buried-channel In0.53Ga0.47 As devices employing an atomic-layer-deposited Al2O3 gate dielectric and a delta-doped InGaAs/InAlAs/InP heterostructure. Peak electron mobilities of 4300 cm(2)/V . s and 6600 cm(2)/V . s at a carrier density of 3 x 10(12) cm(-2) were determined for the surface-and buried-channel structures, respectively. In contrast to similarly scaled inversion-channel devices, we find that the mobility in surface-channel flatband structures does not drop rapidly with the electron density, but rather high mobility is maintained up to carrier concentrations around 4 x 10(12) cm(-2) before slowly dropping to around 2000 cm(2)/V . s at 1 x 10(13) cm(-2). We believe these to be world leading metrics for this material system and an important development in informing the III-V MOSFET device architecture selection process for the future low-power highly scaled CMOS.