Patent ID: 9685565
Date: 2017-06-20
CPC Classifications: H01L

Claim:
1. A semiconductor device comprising: a semiconductor substrate; a gate insulating film for a memory element formed on the semiconductor substrate; and a gate electrode for the memory element formed on the gate insulating film, wherein the gate insulating film has a first insulating film, a second insulating film on the first insulating film, and a third insulating film on the second insulating film, the second insulating film has a charge accumulating function and contains hafnium, silicon, and oxygen, a dielectric constant of the second insulating film is higher than that of silicon nitride, each of the first insulating film and the third insulating film has a band gap larger than a band gap of the second insulating film, and wherein: the second insulating film includes a hafnium oxide of orthorhombic crystal structure, when the atomic ratio of hafnium and silicon in the second insulating film is x:y, the condition 0.79≦x/(x+y)≦0.87 is satisfied, and in said second insulating film, a charge trapping density is from about 5.0×10