| 摘要 |
PROBLEM TO BE SOLVED: To prevent decrease of dielectric withstand voltage when a silicon nitride dielectric film is thinned, by making the nitrogen concentration in the thickness direction of a silicon nitride based dielectric film formed on a substratum material layer be high on the film surface. SOLUTION: A silicon nitride based dielectric film consists of a silicon nitride film 5 and a nitrogen enrichment layer 6. The nitrogen concentration in the film thickness direction is made high on the film surface side. As to the unpaired electrons of silicon atoms in the film, the ratio terminated by nitrogen atoms increases, electron mobility in the film dereases, and characteristics of high dielectric withstand voltage and low leak current can be obtained. It is not the structure wherein oxygen atoms are introduced into the film but essentially a silicon nitride single layer film, and so the possibility that a capacitance value decreases like the NO structure dose not exist. Thereby a dielectric film of high reliability wherein the dielectric withstand voltage is high and the current leak level is low when the film is thinned can be obtained, and initial defect of a semiconductor device is reduced. |
