The low performance of middle infrared (MIR) PbSe detectors fabricated from vapor phase deposition (VPD) technology restricts the rapid development of VPD technology and detector commercialization. A modified VPD process was proposed to duplicate the microstructural features of high-performance CBD-PbSe detectors for a breakthrough in the VPD technology. A peak detectivity D* of 1.6 × 10¹⁰ cm Hz^1/2 W⁻¹ at 298 K was achieved under the optimized sensitization, approaching the best performance of CBD-PbSe detectors. Through the contrasting various microstructures obtained from diverse methods, the nanoparticle self-assembly structure in VPD-PbSe oriented rod-like crystals is an important factor for the IR sensitivity. The microstructural evolution demonstrated that there is a large space to grow for VPD-PbSe detectivity D* via eliminating the voids formed in the iodine-sensitization process. The increased performance indicates that the modified VPD technology can provide technical support for the manufacturing of the megapixel uncooled lead-salt FPA imager and accelerate its industrialization.