MBE Grown Super-saturated Aluminum Delta-doped Layers in Silicon

Recently, significant work has been demonstrated that 2D material systems are important in variety of fields including silicon quantum computing, nanowires, superconductivity, etc. However, most of the studies were focused on n-type dopant layers, a complimentary p-type system has yet to emerge. Here, we report on the detailed material synthesis of this “aluminum delta layer”. Our aluminum delta layers are grown on flash annealed Si (100) substrates by physical vapor deposition and followed by electron-beam evaporated Si epitaxial capping layer. Both in situ and ex situ annealing are studied for dopant activation. Mesa etched Hall bar devices are fabricated to characterize the material properties and the initial results show a p-type carrier contributing to the conduction with densities > 10¹⁴ hole/cm², hole mobility > 10² cm²/Vs and approximately 1.1 holes per dopant atom. Scanning tunneling microscopy (STM) and reflection high-energy electron diffraction (RHEED) images taken during each step of the fabrication processes will also be presented.