An impurity diffusion technique using an excimer laser was studied for the p-type doping of CdTe. A thin layer of Na,Te was evaporated on the CdTe crystal, and laser irradiation decomposed the Na,Te and diffused Na atoms into the Cd site. The resistivity of the top layer of the crystal decreased to below 1 Omega cm and showed p-type conductivity. This technique is applied for fine-patterned p-type doping on the crystal by laser irradiation through a shadow mask. Furthermore, p-i-n CdTe diodes were fabricated for an X-ray imaging device by growing an iodine-doped n-CdTe layer on one side of the crystal and fine-patterned p-type doping on the other side. This device showed good diode properties with a well-saturated reverse bias current and good imaging properties.