Teruo Yokoyama

Reduction of backgating effect in MBE-Grown GaAs/AlGaAs HEMT's

We have investigated the backgating effect in high electron mobility transistors (HEMTs) fabricated on MBE-grown GaAs/AlGaAs layers, which is undesirable for LSI fabrication. Comparing five different types of devices, we related the backgating effect to the interface between the GaAs substrate and the undoped GaAs buffer layer. By using a thermally etched GaAs substrate, we successfully reduced the backgating to the same order as that of ion-implanted GaAs MESFETs.

Se-doped AlGaAs/GaAs HEMTs for stable low-temperature operation

The fabrication of Se-doped AlGaAs/GaAs high electron mobility transistors (HEMTs) is discussed. Because the DX center concentration in Se-doped AlGaAs layers is lower than in Si-doped layers, the drain-current collapses much less at 77 K. The Se-doped HEMTs are therefore suitable for application in low-temperature LSI.<<ETX>>