W(Zn) selectively deposited and locally diffused ohmic contacts to p-InGaAs/InP formed by rapid thermal low pressure metalorganic chemical vapor deposition

Self‐aligned, locally diffused W(Zn) contacts to InGaAs/InP structures were fabricated by means of rapid thermal low pressure metalorganic chemical vapor deposition (RT‐LPMOCVD), using a reactive gas mixture that contained diethylzinc (DEZn), WF6, H2, and Ar. W(Zn) layers of about 30 nm thick were deposited at 500 °C for 20 s and at a total pressure of about 2 Torr, onto InGaAs and InP. Spontaneous formation of highly doped underlying InGaAs and InP layers about 150 nm thick with Zn concentration levels higher than 1×1018 cm−3 took place through the deposition of the W(Zn) layers. Post‐deposition, in situ annealing at temperatures of 500 °C or lower enhanced the indiffusion of Zn into the underlying semiconductor and reduced the specific resistance of the W(Zn)/InGaAs contact to a minimum value of 5×10−6 Ω cm−2.