Semiconductor device and manufacturing method of semiconductor device

Abstract

A highly reliable semiconductor device including an oxide semiconductor is provided. Oxygen is supplied from a base insulating layer provided below an oxide semiconductor layer to a channel formation region, whereby oxygen vacancies which might be generated in the channel formation region are filled. Further, a protective insulating layer containing a small amount of hydrogen and functioning as a barrier layer having a low permeability to oxygen is formed over the gate electrode layer so as to cover side surfaces of an oxide layer and a gate insulating layer that are provided over the oxide semiconductor layer, whereby release of oxygen from the gate insulating layer and/or the oxide layer is prevented and generation of oxygen vacancies in a channel formation region is prevented.

1 . (canceled) 
     
     
         2 . A semiconductor device comprising:
 an oxide semiconductor layer;   a source electrode layer and a drain electrode layer over the oxide semiconductor layer;   an oxide layer over the source electrode layer and the drain electrode layer and in contact with the oxide semiconductor layer;   a gate insulating layer over the oxide layer;   a gate electrode layer over the gate insulating layer; and   a first insulating layer over the gate electrode layer,   wherein the first insulating layer is in contact with the oxide layer and the gate insulating layer,   wherein the oxide semiconductor layer and the oxide layer include at least one metal element in common, and   wherein the first insulating layer comprises one of an aluminum oxide layer, a silicon nitride layer and a silicon nitride oxide layer.   
     
     
         3 . The semiconductor device according to  claim 2 ,
 wherein a concentration of hydrogen in the first insulating layer is lower than 5×10 19  atoms·cm −3 .   
     
     
         4 . The semiconductor device according to  claim 2 , further comprising:
 a second insulating layer over the first insulating layer;   a first conductive layer connected to the source electrode layer through a first opening in the first insulating layer and the second insulating layer; and   a second conductive layer connected to the drain electrode layer through a second opening in the first insulating layer and the second insulating layer,   wherein a thickness of the second insulating layer is larger than a thickness of the first insulating layer.   
     
     
         5 . The semiconductor device according to  claim 2 ,
 wherein in a cross-section of the semiconductor device, an upper edge of the oxide layer coincides with a lower edge of the gate insulating layer.   
     
     
         6 . The semiconductor device according to  claim 2 ,
 wherein the gate insulating layer comprises at least one of a silicon oxide film, a gallium oxide film, an aluminum oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum oxynitride film, a silicon nitride oxide film, and a hafnium oxide film.   
     
     
         7 . The semiconductor device according to  claim 2 ,
 wherein the oxide layer and the oxide semiconductor layer include at least indium, and   wherein an atomic ratio of the indium in the oxide semiconductor layer is higher than an atomic ratio of the indium in the oxide layer.   
     
     
         8 . The semiconductor device according to  claim 7 ,
 wherein the oxide layer and the oxide semiconductor layer include indium, gallium and zinc.   
     
     
         9 . The semiconductor device according to  claim 2 ,
 wherein the oxide semiconductor layer includes a crystal whose c-axis is substantially perpendicular to a surface of the oxide semiconductor layer.   
     
     
         10 . A semiconductor device comprising:
 a first insulating layer;   an oxide semiconductor layer over the first insulating layer;   a source electrode layer and a drain electrode layer over the oxide semiconductor layer;   an oxide layer over the source electrode layer and the drain electrode layer and in contact with the oxide semiconductor layer;   a gate insulating layer over the oxide layer;   a gate electrode layer over the gate insulating layer; and   a second insulating layer over the gate electrode layer,   wherein the second insulating layer is in contact with the oxide layer and the gate insulating layer,   wherein the oxide semiconductor layer and the oxide layer include at least one metal element in common,   wherein the second insulating layer comprises one of an aluminum oxide layer, a silicon nitride layer and a silicon nitride oxide layer, and   wherein the second insulating layer is in contact with the first insulating layer.   
     
     
         11 . The semiconductor device according to  claim 10 ,
 wherein the first insulating layer contains oxygen.   
     
     
         12 . The semiconductor device according to  claim 10 , further comprising:
 a third insulating layer over the second insulating layer;   a first conductive layer connected to the source electrode layer through a first opening in the second insulating layer and the third insulating layer; and   a second conductive layer connected to the drain electrode layer through a second opening in the second insulating layer and the third insulating layer,   wherein a thickness of the second insulating layer is larger than a thickness of the first insulating layer.   
     
     
         13 . The semiconductor device according to  claims 10 ,
 wherein a concentration of hydrogen in the second insulating layer is lower than 5×10 19  atoms·cm −3 .   
     
     
         14 . The semiconductor device according to  claim 10 ,
 wherein in a cross-section of the semiconductor device, an upper edge of the oxide layer coincides with a lower edge of the gate insulating layer.   
     
     
         15 . The semiconductor device according to  claim 10 ,
 wherein the gate insulating layer comprises at least one of a silicon oxide film, a gallium oxide film, an aluminum oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum oxynitride film, a silicon nitride oxide film, and a hafnium oxide film.   
     
     
         16 . The semiconductor device according to  claim 10 ,
 wherein the oxide layer and the oxide semiconductor layer include at least indium, and   wherein an atomic ratio of the indium in the oxide semiconductor layer is higher than an atomic ratio of the indium in the oxide layer.   
     
     
         17 . The semiconductor device according to  claim 16 ,
 wherein the oxide layer and the oxide semiconductor layer include indium, gallium and zinc.   
     
     
         18 . The semiconductor device according to  claim 10 ,
 wherein the oxide semiconductor layer includes a crystal whose c-axis is substantially perpendicular to a surface of the oxide semiconductor layer.