HIGH-TRANSCONDUCTANCE SELF-ALIGNED ALGAN GAN MODULATION-DOPED FIELD-EFFECT TRANSISTORS WITH REGROWN OHMIC CONTACTS/

Self-aligned AlGaN/GaN modulation-doped field-effect transistors with high (MODFETs) transconductances have been demonstrated on a sapphire substrate. Source and drain were selectively regrown with similar to 1 700 Angstrom of n-GaN adjacent to the gate electrode. Source resistanc e was reduced to 0.95 Ohm mm from 1.4 to 1.8 Ohm mm with conventional GaN-based MODFETs. These self-aligned devices show a record high value of extrinsic transconductance similar to 400 mS/mm for AlGaN/GaN MODF ETs with a gate length of 1.2 mm. (C) 1998 American Institute of Physi cs. [S0003-6951(98)03047-2].