Epitaxial growth of heavily doped n+-Ge layers using metal-organic chemical vapor deposition with in situ phosphorus doping

We report the epitaxy of n-Ge layer with in situ phosphorus (P)-doping using metal-organic chemical vapor deposition (MOCVD) method with tertiary-butyl-germane and tri-ethyl-phosphine precursors. The crystalline and electrical properties of n-Ge epitaxial layers have been investigated using X-ray diffraction, atomic force microscopy, and Hall effect measurements in detail. In situ P-doping with MOCVD demonstrates the incorporation of P in Ge as high as 1 × 1020 cm−3. The electron concentration in P-doped Ge epitaxial layers are achieved as high as 1.7 × 1019, 1.8 × 1019, and 2.2 × 1018 cm−3 at growth temperatures of 400, 350, 320 °C, respectively.