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, Ni
₂
P thin films were developed on a 300 mm platform. The Ni
₂
P layers, obtained by magnetron sputtering of a Ni
₂
P target, were stable and reproducible. The films were mainly composed of the hexagonal Ni
₂
P phase with small amount of Ni
₁₂
P
₅
impurities. The film density was 6.9 g/cm
³
with a ratio of 62 at.% of Ni and 38 at.% of P. We implemented and integrated these Ni
₂
P 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, Ni
₂
P metallization exhibited the best results among the Ni-based metallizations studied for contacting n-InP layers, namely Ni, NiPt and Ni
₂
P.