Semiconductor device and manufacturing method thereof

Abstract

A semiconductor device includes a substrate having a first area and a second area adjacent to the first area, a first silicon layer provided on the substrate in the first area, a relaxed layer which is provided on the substrate in the second area and which has a lattice constant greater than a lattice constant of the first silicon layer, and a strained-Si layer which is provided on the relaxed layer and which has a lattice constant substantially equivalent to the lattice constant of the relaxed layer.

1 . A semiconductor device comprising: 
 a substrate having a first area and a second area adjacent to the first area;    a first silicon layer provided on the substrate in the first area;    a relaxed layer which is provided on the substrate in the second area and which has a lattice constant greater than a lattice constant of the first silicon layer; and    a strained-Si layer which is provided on the relaxed layer and which has a lattice constant substantially equivalent to the lattice constant of the relaxed layer.    
   
   
       2 . The semiconductor device according to  claim 1 , further comprising a buffer film provided between the first silicon layer and the relaxed layer.  
   
   
       3 . The semiconductor device according to  claim 1 , wherein the substrate is a silicon substrate, and 
 the semiconductor device further comprises a buffer layer provided between the relaxed layer and the silicon substrate, a lattice constant of the buffer layer becoming greater than a lattice constant of silicon toward a top surface of the buffer layer.    
   
   
       4 . The semiconductor device according to  claim 1 , wherein the substrate is a SOI (Silicon On Insulator) substrate, and 
 the substrate includes an insulation layer and a second silicon layer provided on the insulation layer.    
   
   
       5 . The semiconductor device according to  claim 1 , further comprising an insulation layer provided between the substrate and the first silicon layer.  
   
   
       6 . The semiconductor device according to  claim 1 , further comprising an insulation layer provided between the substrate and the relaxed layer.  
   
   
       7 . The semiconductor device according to  claim 1 , wherein the relaxed layer is formed of silicon germanium.  
   
   
       8 . The semiconductor device according to  claim 1 , wherein the buffer film is formed of SiN.  
   
   
       9 . The semiconductor device according to  claim 1 , wherein the first area is an area in which a memory device and/or an analog device is formed, and 
 the second area is an area in which a digital device is formed.    
   
   
       10 . The semiconductor device according to  claim 9 , wherein the memory device includes at least one of a DRAM (Dynamic Random Access Memory), an SRAM (Static Random Access Memory) and a flush memory, 
 the analog device includes at least one of a capacitor and an amplifying element which processes a high-frequency signal, and    the digital device includes a CMOS (Complementary Metal Oxide Semiconductor) device.    
   
   
       11 . A semiconductor device comprising: 
 a silicon substrate having a first area, a second area adjacent to the first area, and a protrusion arranged in the first area;    a relaxed layer which is provided on the silicon substrate in the second area and which has a lattice constant greater than a lattice constant of the silicon substrate; and    a strained-Si layer which is provided on the relaxed layer and which has a lattice constant substantially equivalent to the lattice constant of the relaxed layer.    
   
   
       12 . The semiconductor device according to  claim 11 , further comprising a buffer film provided between the protrusion and the relaxed layer.  
   
   
       13 . The semiconductor device according to  claim 11 , further comprising a buffer layer provided between the relaxed layer and the silicon substrate, a lattice constant of the buffer layer becoming greater than a lattice constant of silicon toward a top surface of the buffer layer.  
   
   
       14 . The semiconductor device according to  claim 11 , wherein the silicon substrate is a SOI substrate, and 
 the silicon substrate includes an insulation layer and a silicon layer provided on the insulation layer.    
   
   
       15 . The semiconductor device according to  claim 11 , further comprising an insulation layer provided in the silicon substrate and below the protrusion.  
   
   
       16 . A method of manufacturing a semiconductor device, comprising: 
 preparing a substrate having a first area and a second area adjacent to the first area;    forming on the substrate a relaxed layer which has a lattice constant greater than a lattice constant of silicon;    coating the relaxed layer of the second area with a resist film;    etching the relaxed layer by using the resist film as a mask;    removing the resist film;    forming a first silicon layer on the substrate in the first area; and    forming a strained-Si layer on the relaxed layer by epitaxial growth.    
   
   
       17 . The method according to  claim 16 , further comprising forming a buffer film on each of side surfaces of the relaxed layer after removing the resist film.  
   
   
       18 . The method according to  claim 16 , wherein the substrate is a SOI substrate.  
   
   
       19 . A method of manufacturing a semiconductor device, comprising: 
 preparing a silicon substrate having a first area and a second area adjacent to the first area;    coating the silicon substrate in the first area with a resist film;    etching the silicon substrate by using the resist film as a mask to form a protrusion on the silicon substrate;    removing the resist film;    forming a relaxed layer which has a lattice constant greater than a lattice constant of the silicon substrate, on the silicon substrate in the second area; and    forming a strained-Si layer on the relaxed layer by epitaxial growth.    
   
   
       20 . The method according to  claim 19 , further comprising forming a buffer film on each of both side surfaces after removing the resist film.