Fig. 1. Profile diagram and internal electric field distribution of InGaAs/InP APD structure

Fig. 2. Hall carrier concentration and mobility plot

Fig. 3. TRPL spectra of APD wafers

Fig. 4. (a) Comparison of SIMS depth distributions for Samples via As₄, P₂ deoxidation，(b) Bulk regions (d = 4.8-5.6 μm) of comparison of deoxidation interface

Fig. 5. STEM-HAADF image of APD sample A（As-deoxidation）（a）an image of the APD structure on FIB grid，（b）the image of InGaAs and InP buffer，（c）zoom region of InP homojunction interfaces，（d）high-resolution images of the region marked with a red frame in（a）

Fig. 6. STEM-HAADF image of APD sample B（P-deoxidation）（a）an image of the APD structure on the FIB grid，（b）the image of InGaAs and InP buffer，（c）the zoom region of InP homojunction interfaces and stacking fault（circled）. Circles indicate dislocations with different core structures，（d）high-resolution images of the area marked with a red frame in（a）

Fig. 7. (a) I-V and gain characteristics of the InGaAs/InP APD，(b) TRPL spectra of ARC-APD

Table 1. Average peak concentrations (cm^-3 ) of impurities in bulk regions (d = 4.8-5.6 μm) from SIMS measurements.