The n(+)-type silicon island was fabricated using double diffusion, selective anodization and oxidation of silicon. The island was applied as a heating resistor of a thermal inkjet printhead. The heating, resistor has good uniformity of +/-5% and good endurance of 10(8) cycles under electrical stresses. In the inkjet printhead structure, high-quality thermal oxide can be used as a passivation layer and a thick thermal barrier oxide under heating resistors can be easily achieved. The diameter of ejected ink dots with a nozzle diameter of 35 mu m was about 100 mu m. There were no satellites on the paper.