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 5×10−8 Ω 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 4.4×1020 cm−3. Regrown contacts with planar and lateral p+/p structures are fabricated to clarify interface contact resistivities. A fairly low value of 7.1×10−8 Ω 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.