OHMIC CONTACTS TO P-GAAS WITH P+/P REGROWN STRUCTURES FORMED BY METALORGANIC MOLECULAR-BEAM EPITAXY

Excellent ohmic contacts to p-GaAs are fabricated using selective growth by metalorganic molecular beam epitaxy. Specific contact resistance of about 5 X 10(-8) OMEGA-cm2 is achieved, without any heat treatment, at AuMn/Au and Ti/Pt/Au metal contacts, formed on p+-GaAs layers heavily carbon-doped to 4.4 X 10(20) cm-3. Regrown contacts with planar and lateral p+/p structures are fabricated to clarify interface contact resistivities. A fairly low value of 7.1 X 10(-8) OMEGA-cm2 is established, using an equivalent circuit model, for the lateral contacts to thin p-GaAs layers, reasonably independent of its thicknesses in the range of 9.5-95 nm. These results, in addition to excellent growth selectivity, have confirmed prospects for practical use.