Red InGaP light-emitting diodes epitaxially grown on engineered Ge-on-Si substrates

Abstract

The integration of light emitting devices on silicon substrates has attracted intensive research for many years. In contrast to the InGaN light emitting diodes (LEDs) whose epitaxy technology on Si substrates is robust and mature, the epitaxy of other compound semiconductor light emitting materials covering the visible wavelength range on Si is still challenging. We have studied epitaxial growth of red InGaP light emitting materials on engineered Ge-on-Si substrates. Ge-on-Si was grown on 8'' Si substrates in a metal organic chemical vapour deposition (MOCVD) reactor using two- step growth and cycling annealing. Threading dislocation densities (TDDs) were controlled to as low as 10⁶ /cm² by using As-doped Ge initiation. A GaAs buffer layer and lattice-matched InGaP LEDs were grown on the Ge-on-Si sequentially in the same MOCVD process and red LEDs are demonstrated. InGaP multiple-quantum-well LED structures were grown on full 8″ Ge-on-Si substrates and characterized.