Crack-free GaAs epitaxy on Si by using midpatterned growth:Application to Si-based wavelength-selective photodetector

A monolithically integrated wavelength-selective photodetector, which consists of an 11.86 μ m thick GaAs-based Fabry-Pérot filter and a 3.84 μ m thick InP-based p - i - n absorption structure (with a 0.3 μ m In 0.53 Ga 0.47 As absorption layer), was grown on a Si substrate. A crack-free and high-quality epilayer with an area of 800 × 700 μ m 2 was obtained by using midpatterned growth and thermal-cycle annealing. Long dislocations running parallel to the GaAs/Si interface were formed by thermal annealing. This kind of dislocation may effectively alleviate the thermal stress across a large patterned area and be responsible for the crack-free epilayer. A photodetector with a spectral linewidth of 1.1 nm (full width at half maximum) and a quantum efficiency of 9.0% was demonstrated.