Excellent surface flatness of HgCdTe wafers is essential for fabricating large infrared focal plane arrays (IRFPAs) within the framework of a flip-chip bonding yield. However, liquid-phase epitaxy (LPE) HgCdTe wafers, which are widely used for IRFPAs, have inherent problems pertaining to surface flatness. In this study, we introduced a single-point diamond turning (SPDT) method for use in fabricating LPE HgCdTe photodiodes. The cutoff wavelength of the wafers is similar to 5 mu m. The surface roughness of the LPE HgCdTe wafer has been substantially reduced but a type-converted defective layer was formed on the surface of the HgCdTe wafer after SPDT, which was confirmed using Hall and capacitance-voltage (C-V) measurements. The defective layer, however, was easily removed by bromine in methanol (Br-MeOH) etching. The fabricated photodiode showed a dynamic resistance-area product at the zero bias (R(0)A) value of similar to 1 x 10(4) Omega cm(2) for a junction area of 30 x 30 mu m(2) at 80 K, which is equivalent to that of a conventional photodiode. The flip-chip bonding efficiency has been remarkably improved from 89.43% to 99.99% for 320 x 256 IRFPA at room temperature after SPDT.