Ultralow dark current Ge/Si(100) photodiodes with low thermal budget

Vertical incidence photodiodes were fabricated from Ge grown epitaxially on Si(100) by low-energy plasma-enhanced chemical vapor deposition. Consideration of the energy band profiles of n-i-p and p-i-n heterostructures, and optimization of growth processes and thermal budget, allowed the performance of Ge photodectors integrated on Si(100) substrates to be optimized. Record low dark current density of Js=4.1×10−5 A/cm2 and external quantum efficiency at 1550 nm of η=32% were measured.