Low-noise and high-quantum-efficiency germanium APD’s have been investigated by a p+-n structure. Boron implantation was used to form the p+ layer. Shallow p+-n junctions have a lower excess noise that n+-p junctions because holes have a higher ionization coefficient in germanium, and these p+-n diodes have a higher hole-to-electron collection efficiency. Excess noise factors F≈7 at a multiplication factor of 10 are obtained at wavelength of ∼1.4 μm, whereas F≈11 for n+-p diodes. An internal quantum efficiency of ∼80% is obtained at 1.15 μm.