MANUFACTURE OF SEMICONDUCTOR DEVICE

PURPOSE:To simultaneously form two or more impurity diffusion layers with different impurity concentrations and/or different diffusion depths by means of one thermal diffusion operation by a method wherein a BSG film or a PSG film is used as an impurity diffusion source and a silicon nitride film and a silicon dioxide film are used as diffusion control films. CONSTITUTION:A silicon dioxide film 2 is formed on an n-type silicon semiconductor layer 1; it is patterned; openings 3, 4 and 5 are formed in regions used to form impurity diffusion layers. Then, a borosilicate glass (BSG) film 6 is formed on the whole surface. A silicon nitride film 7 is formed on the whole surface; it is patterned; the silicon nitride film 7 is left on the BSG film 6 corresponding to the opening 4. Then, a silicon dioxide film is formed again on the whole surface; it is patterned; the silicon dioxide film 8 is left on the BSG film 6 coming into contact with the opening 5. After that, an annealing operation is executed; impurity boron in the ESG film 6 is diffused into the n-type silicon semiconductor layer 1; p-type impurity diffusion layers 9, 10, 11 are formed.