Ex parte YOSHIDA et al. - Page 12

          Appeal No. 95-1555                                                          
          Application 07/871,530                                                      

               In column 3, lines 15-28, Anderson further teaches that                
          Figures 2 and 3 shows the trench capacitors 16a and 16b extend              
          through P-tank 40 into the P substrate 48.  Anderson further                
          teaches that on the outside of the trench capacitor walls, the              
          storage node material, arsenic, is implanted creating an                    
          implanted arsenic layer 50.  The arsenic layer 50 creates the N+            
          storage node of the trench capacitors.  The upper portion of the            
          storage node on the top of the trench edge where the leakage                
          current could flow into the P-tank 40 is indicated by reference             
          numeral 51.  Anderson teaches in column 3, lines 50-61, that the            
          P-tank 40 is implanted by an increased dopant over the p type               
          substrate 48.  Anderson teaches that the purpose of the increased           
          dopant p-tank layer 40 is to control trench capacitance leakage             
          and latchup.                                                                
               Tsuchiya is also concerned with trench capacitor type high             
          density dynamic random access memories.  Thus, Tsuchiya’s trench            
          capacitor type high density dynamic random access memories are              
          subject to the same problems recognized by Anderson.                        
               Those skilled in the art having both the teachings of                  
          Tsuchiya and Anderson before them would have recognized from the            
          teachings of Anderson that it would have been desirable to use              
          the Anderson method of doping of the storage node and the                   


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