fabricating processes of silicon planar n-p-n transistors are described. These processes include materical preparation, oxidation, photoresist, boron diffusion, phosphorous diffusion, and aluminium metalizing. Boron layer has been diffused in n type silicon from B2O3-SiO2 source using the box method, Phosporous layer has been diffused from P2O5-SiO2 source with the same method. The planar diodes are also fabricated by the processes described above.