ON THE DETERMINATION OF THE SPECIFIC CONTACT RESISTANCE OF ALLOYED CONTACTS TO N-GAAS

The popular distributed model for metal-semiconductor ohmic contacts is extended to take into account the nonplanar nature of alloyed contacts. AuGe/Ni ohmic contacts are fabricated on n-GaAs epitaxial layers (3×1018cm-3, 160 nm) with an undoped cap layer of varied thickness. Thus the specific contact resistance and the so-called alloyed depth are determined from the measured contact resistances. Typical values are, respectively, 10-7Ω·cm2and 250 nm. © 1990 IOP Publishing Ltd.