Semiconductor device and manufacturing method thereof

Abstract

The present invention provides a semiconductor device that reduces the junction leak current and achieves an improvement in the reliability of the gate oxide film by minimizing divot formation and the occurrence of a kink and a method of manufacturing such a semiconductor device. A pad oxide film and a silicon nitride film are formed on an Si substrate and a groove-like trench is formed through photolithography and etching. The liner oxide of the trench are oxidized through oxidizing/nitriding. Then, the trench is filled with an insulating film, the insulating film is planarized and the silicon nitride film and the pad oxide film are removed. Next, a field area is formed and a transistor is formed by following specific steps. By forming a trench liner oxide film containing nitrogen, stress is reduced.

1. A method of fabricating a semiconductor device, the method comprising:
 providing a substrate;    forming a pad oxide film and a silicon nitride film over the substrate;    forming a trench;    forming a liner oxide at least in the trench by an oxidizing step, an nitriding step and another oxidizing step; and    substantially filling the trench with an insulating film, performing a planarizing step to remove the pad oxide and the silicon nitride film that are over the substrate.    
     
     
       2. A method of fabricating a semiconductor device, the method comprising:
 providing a substrate;    forming a pad oxide film and a silicon nitride film over the substrate;    forming a trench;    forming a liner oxide at least in the trench by an oxidizing step;    substantially filling the trench with an insulating film, performing a planarizing step to remove the pad oxide and the silicon nitride film that are over the substrate;    forming a sacrificial oxide layer by performing an oxidizing step, a nitriding step and another oxidizing step; and    performing an ion implantation step.    
     
     
       3. A method of fabricating a semiconductor device, the method comprising:
 providing a substrate;    forming a pad oxide film and a silicon nitride film over the substrate;    forming a trench;    forming a liner oxide at least in the trench by an oxidizing step, an nitriding step and another oxidizing step; and    substantially filling the trench with an insulating film, performing a planarizing step to remove the pad oxide and the silicon nitride film that are over the substrate; and    forming a sacrificial oxide layer by performing an oxidizing step, a nitriding step and another oxidizing step.    
     
     
       4. A method of fabricating a semiconductor device, the method comprising:
 providing a substrate;    forming a pad oxide film and a silicon nitride film over the substrate;    forming a trench;    forming a liner oxide at least in the trench by an oxidizing step, an nitriding step and another oxidizing step; and    substantially filling the trench with an insulating film, performing a planarizing step to remove the pad oxide and the silicon nitride film that are over the substrate; and    forming a gate oxide by an oxidizing step, a nitriding step and another oxidizing step.    
     
     
       5. A method of fabricating a semiconductor device, the method comprising:
 providing a substrate;    chemical vapor depositing a TEOS pad oxide film over the substrate and annealing the pad oxide film by a rapid thermal anneal step    forming a silicon nitride film over the pad oxide;    forming a trench;    forming a liner oxide at least in the trench by an oxidizing step, an nitriding step and another oxidizing step; and    substantially filling the trench with an insulating film, performing a planarizing step to remove the pad oxide and the silicon nitride film that are over the substrate; and    forming gate oxide layer by performing an oxidizing step, a nitriding step and another oxidizing step.    
     
     
       6. A method of fabricating a semiconductor device, the method comprising:
 providing a substrate;  
 chemical vapor depositing a TEOS pad oxide film over the substrate and annealing the pad oxide film by a rapid thermal anneal step: 
 forming a silicon nitride film over the pad oxide;  
 etching the silicon nitride film after performing a photolithographic process;  
 forming a sacrificial local oxidation of silicon layer by an oxidizing step, a nitriding step and another oxidizing step  and a nitriding step;  
 forming a trench;  
 forming a liner oxide at least in the trench by an oxidizing step, a nitriding step and another oxidizing step; and  
 substantially filling the trench with an insulating film, performing a planarizing step to remove the pad oxide and the silicon nitride film that are over the substrate; and  
 forming gate oxide layer by performing an oxidizing step, a nitriding step and another oxidizing step.