Ohmic InP/Si direct-bonded heterointerfaces

Abstract

Directly bonded ohmic InP/Si heterostructures are realized, overcoming the large (8%) lattice mismatch. By employing proper semiconductor surface pretreatments including cleaning and oxide removal, we obtain ohmic interfacial electrical characteristics at a bonding temperature as low as 200 °C. Among the doping-polarity combinations, ohmic interfacial electrical characteristics are observed for n-InP/n-Si and n-InP/p-Si bonded heterointerfaces, but not for p-InP/p-Si and p-InP/n-Si pairs. We numerically explain this polarity dependence in terms of energy band connections across the InP/Si heterointerfaces. The highly conductive III-V/Si direct bonding technique developed in this study is applicable for various heterostructured optoelectronic devices, such as multijunction solar cells and photonic integrated circuits.