$Hg_{0.78}Cd_{0.22}Te$ diodes have been fabricated by employing an ion-implantation technique and hybridized with Si which have metal pads and Indium bumps using flip-chip bonder. The performances of the diodes, prior to and after annealing at 120℃ which is performed after hybrid bonding, have been investigated. Prior to the annealing process, dark currents are limited by band-to-band and trap-assisted tunneling current owing to high concentration of $N_D$ and $N_t$ But, after annealing, diode characteristics are improved dramatically, namely, RoA values are incresed and dark currents at reverse bias are reduced. Over 160 diodes are compared prior to and after annealing and all of them show these improvements. These results were compared with computer calculation and the improvements are explained by changes in both carrier concentration profile and pn junction position during the annealing process. Donor concentration $N_D$ was changed from 1×$10^{18}$ to 3×$10^{16}$ and trap density was changed from 9.2×$10^{16}$ to 7.3×$10^{16}$.
