Semiconductor device and method for manufacturing the same

Abstract

A semiconductor device includes a semiconductor substrate, a first insulating film formed on the semiconductor substrate, a charge storage layer formed on the first insulating film, a second insulating film formed on the charge storage layer, and a control electrode formed on the second insulating film, the second insulating film including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film.

1 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film.   
   
   
       2 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film having one of a first film structure, a second film structure, and a third film structure,   the first film structure including a lower silicon oxide film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon oxide film formed on the intermediate insulating film,   the second film structure including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film,   the third film structure including a lower silicon nitride film, an intermediate insulating film formed on the lower silicon nitride film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon nitride film formed on the intermediate insulating film,   the intermediate insulating film having a thickness equal to or greater than that of one atomic layer and equal to or smaller than 5 nm.   
   
   
       3 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film having one of a first film structure and a second film structure,   the first film structure including a lower silicon oxide film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon oxide film formed on the intermediate insulating film,   the second film structure including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film,   the intermediate insulating film being formed of a polycrystalline film, and crystal grains contained in the polycrystalline film having an average grain size of at least 5 nm.   
   
   
       4 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film having one of a first film structure, a second film structure, and a third film structure,   the first film structure including a lower silicon oxide film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon oxide film formed on the intermediate insulating film,   the second film structure including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film,   the third film structure including a lower silicon nitride film, an intermediate insulating film formed on the lower silicon nitride film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon nitride film formed on the intermediate insulating film,   wherein the following expression is satisfied,
     T /( T+M+S )≧0.2 
   
     where T (T>0) is a concentration of a transition metal element in the intermediate insulating film, M (M≧0) is a concentration of a metal element other than the transition metal element in the intermediate insulating film, and S (S≧0) is a concentration of a semiconductor element in the intermediate insulating film. 
   
   
       5 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film having one of a first film structure, a second film structure, and a third film structure,   the first film structure including a lower silicon oxide film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon oxide film formed on the intermediate insulating film,   the second film structure including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film,   the third film structure including a lower silicon nitride film, an intermediate insulating film formed on the lower silicon nitride film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon nitride film formed on the intermediate insulating film,   the intermediate insulating film having a carbon concentration of at least 1×10 19  atoms/cm 3  and at most 2×10 22  atoms/cm 3 .   
   
   
       6 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film having one of a first film structure, a second film structure, and a third film structure,   the first film structure including a lower silicon oxide film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon oxide film formed on the intermediate insulating film,   the second film structure including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film,   the third film structure including a lower silicon nitride film, an intermediate insulating film formed on the lower silicon nitride film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon nitride film formed on the intermediate insulating film,   the intermediate insulating film having a nitrogen concentration of at least 1×10 19  atoms/cm 3  and at most 2×10 22  atoms/cm 3 .   
   
   
       7 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film having one of a first film structure, a second film structure, and a third film structure,   the first film structure including a lower silicon oxide film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon oxide film formed on the intermediate insulating film,   the second film structure including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film,   the third film structure including a lower silicon nitride film, an intermediate insulating film formed on the lower silicon nitride film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon nitride film formed on the intermediate insulating film,   the intermediate insulating film having a hydrogen concentration of at least 1×10 19  atoms/cm 3  and at most 5×10 22  atoms/cm 3 .   
   
   
       8 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film having one of a first film structure and a second film structure,   the first film structure including a lower silicon oxide film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon oxide film formed on the intermediate insulating film,   the second film structure including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film,   at least one of the lower silicon oxide film and the upper silicon oxide film being thicker than the intermediate insulating film.   
   
   
       9 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film having one of a first film structure and a second film structure,   the first film structure including a lower silicon oxide film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon oxide film formed on the intermediate insulating film,   the second film structure including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film,   at least one of the lower silicon oxide film and the upper silicon oxide film having a carbon concentration of at least 1×10 19  atoms/cm 3 .   
   
   
       10 . A semiconductor device comprising:
 a semiconductor substrate;   a first insulating film formed on the semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film having one of a first film structure and a second film structure,   the first film structure including a lower silicon oxide film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, and an upper silicon oxide film formed on the intermediate insulating film,   the second film structure including a lower silicon nitride film, a lower silicon oxide film formed on the lower silicon nitride film, an intermediate insulating film formed on the lower silicon oxide film and containing a metal element, the intermediate insulating film having a relative dielectric constant of greater than 7, an upper silicon oxide film formed on the intermediate insulating film, and an upper silicon nitride film formed on the upper silicon oxide film,   at least one of the lower silicon oxide film and the upper silicon oxide film having a chlorine concentration of at least 1×10 19  atoms/cm 3 .   
   
   
       11 . A semiconductor device having a plurality of memory cells each comprising:
 a first insulating film formed on a semiconductor substrate;   a charge storage layer formed on the first insulating film;   a second insulating film formed on the charge storage layer; and   a control electrode formed on the second insulating film,   the second insulating film including a high dielectric constant insulating film containing a metal element and having a relative dielectric constant of greater than 7,   the high dielectric constant insulating film having a first part formed along a top surface of the charge storage layer, a second part formed along a side surface of the charge storage layer, and a third part formed between the adjacent charge storage layers,   the third part having a lower oxygen concentration than the first part.   
   
   
       12 . A method for manufacturing a semiconductor device, the method comprising:
 forming a first insulating film on a semiconductor substrate;   forming a charge storage layer on the first insulating film;   forming a second insulating film on the charge storage layer; and   forming a control electrode film on the second insulating film,   forming the second insulating film including one of forming a first film structure, forming a second film structure, and forming a third film structure,   forming the first film structure including forming a lower silicon oxide film, forming an intermediate insulating film on the lower silicon oxide film, the intermediate insulating film containing a metal element and oxygen and having a relative dielectric constant of greater than 7, and forming an upper silicon oxide film on the intermediate insulating film;   forming the second film structure including forming a lower silicon nitride film, forming a lower silicon oxide film on the lower silicon nitride film, forming an intermediate insulating film on the lower silicon oxide film, the intermediate insulating film containing a metal element and oxygen and having a relative dielectric constant of greater than 7, forming an upper silicon oxide film on the intermediate insulating film, and forming an upper silicon nitride film on the upper silicon oxide film;   forming the third film structure including forming a lower silicon nitride film, forming an intermediate insulating film on the lower silicon nitride film, the intermediate insulating film containing a metal element and oxygen and having a relative dielectric constant of greater than 7, and forming an upper silicon nitride film on the intermediate insulating film,   the intermediate insulating film being formed by CVD or ALD using ozone or oxygen radicals as an oxygen source.   
   
   
       13 . A method for manufacturing a semiconductor device, the method comprising:
 forming a first insulating film on a semiconductor substrate;   forming a charge storage layer on the first insulating film;   forming a second insulating film on the charge storage layer; and   forming a control electrode film on the second insulating film,   forming the second insulating film including one of forming a first film structure, forming a second film structure, and forming a third film structure,   forming the first film structure including forming a lower silicon oxide film, forming an intermediate insulating film on the lower silicon oxide film, the intermediate insulating film containing a metal element and oxygen and having a relative dielectric constant of greater than 7, and forming an upper silicon oxide film on the intermediate insulating film;   forming the second film structure including forming a lower silicon nitride film, forming a lower silicon oxide film on the lower silicon nitride film, forming an intermediate insulating film on the lower silicon oxide film, the intermediate insulating film containing a metal element and oxygen and having a relative dielectric constant of greater than 7, forming an upper silicon oxide film on the intermediate insulating film, and forming an upper silicon nitride film on the upper silicon oxide film;   forming the third film structure including forming a lower silicon nitride, forming an intermediate insulating film on the lower silicon nitride film, the intermediate insulating film containing a metal element and oxygen and having a relative dielectric constant of greater than 7, and forming an upper silicon nitride film on the intermediate insulating film,   the intermediate insulating film being formed by CVD or ALD using water vapor as an oxygen source.   
   
   
       14 . A method for manufacturing a semiconductor device, the method comprising:
 forming a first insulating film on a semiconductor substrate;   forming a charge storage layer on the first insulating film;   forming a second insulating film on the charge storage layer; and   forming a control electrode film on the second insulating film,   forming the second insulating film including one of forming a first film structure, forming a second film structure, and forming a third film structure,   forming the first film structure including forming a lower silicon oxide film, forming an intermediate insulating film on the lower silicon oxide film, the intermediate insulating film containing a metal element and oxygen and having a relative dielectric constant of greater than 7, and forming an upper silicon oxide film on the intermediate insulating film;   forming the second film structure including forming a lower silicon nitride film, forming a lower silicon oxide film on the lower silicon nitride film, forming an intermediate insulating film on the lower silicon oxide film, the intermediate insulating film containing a metal element and oxygen and having a relative dielectric constant of greater than 7, forming an upper silicon oxide film on the intermediate insulating film, and forming an upper silicon nitride film on the upper silicon oxide film;   forming the third film structure including forming a lower silicon nitride film, forming an intermediate insulating film on the lower silicon nitride film, the intermediate insulating film containing a metal element and oxygen and having a relative dielectric constant of greater than 7, and forming an upper silicon nitride film on the intermediate insulating film,   forming the second insulating film including, after forming the intermediate insulating film, performing a heat treatment at a temperature higher than that at which the intermediate insulating film is formed.   
   
   
       15 . A method for manufacturing a semiconductor device, the method comprising:
 forming a first insulating film on a semiconductor substrate;   forming a charge storage layer on the first insulating film;   forming a second insulating film on the charge storage layer; and   forming a control electrode film on the second insulating film,   forming the second insulating film including one of forming a second film structure, and forming a third film structure,   forming the second film structure including forming a lower silicon nitride film, forming a lower silicon oxide film on the lower silicon nitride film, forming an intermediate insulating film on the lower silicon oxide film, the intermediate insulating film containing a metal element and having a relative dielectric constant of greater than 7, forming an upper silicon oxide film on the intermediate insulating film, and forming an upper silicon nitride film on the upper silicon oxide film;   forming the third film structure including forming a lower silicon nitride film, forming an intermediate insulating film on the lower silicon nitride film, the intermediate insulating film containing a metal element and having a relative dielectric constant of greater than 7, and forming an upper silicon nitride film on the intermediate insulating film,   forming the second insulating film including, after forming the lower silicon nitride film, performing a heat treatment at a temperature higher than that at which the lower silicon nitride film is formed.   
   
   
       16 . A method for manufacturing a semiconductor device, the method comprising:
 forming a first insulating film on a semiconductor substrate;   forming a charge storage layer on the first insulating film;   forming a second insulating film on the charge storage layer; and   forming a control electrode film on the second insulating film,   forming the second insulating film including forming a silicon nitride film on the charge storage layer,   forming the silicon nitride film including forming a silicon layer on the charge storage layer and nitriding the silicon layer.