Development of Ni₂P Contact Technology and Its Integration on III-V Materials for 300 mm Si Photonics Platform

In order to assess their potential use as contact layers for Si photonics devices, Ni2P thin films were developed on a 300 mm platform. The Ni2P layers, obtained by magnetron sputtering of a Ni2P target, were stable and reproducible. The films were mainly composed of the hexagonal Ni2P phase with small amount of Ni12P5 impurities. The film density was 6.9 g/cm3 with a ratio of 62 at.% of Ni and 38 at.% of P. We implemented and integrated these Ni2P films on III-V structures to study their electrical properties on n-InP and p-InGaAs (i.e., n-doped and p-doped III-V/Si hybrid laser contact layers). The results obtained on p-InGaAs did not meet the requirements in terms of contact resistivity. On the other hand, due to its high thermal stability and low contact resistivities, Ni2P metallization exhibited the best results among the Ni-based metallizations studied for contacting n-InP layers, namely Ni, NiPt and Ni2P.