MOS image pick-up device and camera incorporating the same

Abstract

A MOS image pick-up device including a semiconductor substrate, an imaging region formed on the semiconductor substrate by arraying plural unit pixels, and a peripheral circuit region including a driving circuit for operating the imaging region formed on the semiconductor substrate; the unit pixels include a photodiode, MOS (metal-oxide-semiconductor) transistors and a first device-isolation portion, the peripheral circuit region includes a second device-isolation portion for isolating devices in the driving circuit; wherein each of the first device-isolation portion and the second device-isolation portion is at least one portion selected from an electrically insulating film formed on the substrate in order not to erode the substrate, a electrically insulating film formed on the substrate so as to erode the substrate to a depth ranging from 1 nm to 50 nm, and an impurity diffusion region formed within the substrate. The MOS image pick-up device is incorporated in a camera. Thereby, devices are isolated between MOS transistors, and noise caused by leakage current is decreased.

1. A MOS (metal-oxide-semiconductor) image pick-up device comprising:
 a semiconductor substrate,  
 an imaging region formed on the semiconductor substrate by arraying plural unit pixels, and  
 a peripheral circuit region comprising a driving circuit for operating the imaging region formed on the semiconductor substrate;  
 where each of the unit pixels comprises: a photodiode, MOS transistors, and a first device-isolation portion comprising a portion next to the photodiode and a portion not next to the photodiode, and  
 the peripheral circuit region comprises a second device-isolation portion for isolating devices in the driving circuit,  
 wherein the following are satisfied:  
 I. each of the first device-isolation portion not next to the photodiode and the second device-isolation portion has a structure comprising: 
 A. an electrically insulating film formed on a surface of the substrate so as to erode the substrate to a depth in a range of 1 nm to 50 nm, or  
 B. both an electrically insulating film formed on a surface of the substrate so as to erode the substrate to a depth in a range of 1 nm to 50 nm and an impurity diffusion region formed within the substrate, and  
 
 II. each of the first device-isolation portions next to the photodiode has a structure consisting of only an impurity diffusion region formed within the substrate directly under the substrate surface.  
 
     
     
       2. The MOS image pick-up device according to  claim 1 , wherein the impurity diffusion region is formed by ion implantation. 
     
     
       3. The MOS image pick-up device according to  claim 1 , wherein at least one part of the driving circuit is a dynamic circuit. 
     
     
       4. The MOS image pick-up device according to  claim 1 , wherein the photodiode has a surface portion having a dark current inhibiting layer. 
     
     
       5. The MOS image pick-up device according to  claim 1 , wherein the first device-isolation portion and the second device-isolation portion are formed by annealing in a hydrogen atmosphere. 
     
     
       6. A camera comprising a MOS (metal-oxide-semiconductor) image pick-up device comprising:
 a semiconductor substrate,  
 an imaging region formed on the semiconductor substrate by arraying plural unit pixels, and  
 a peripheral circuit region comprising a driving circuit for operating the imaging region formed on the semiconductor substrate;  
 where each of the unit pixels comprises: a photodiode, MOS transistors, and a first device-isolation portion comprising a portion next to the photodiode and a portion not next to the photodiode, and  
 the peripheral circuit region comprises a second device-isolation portion for isolating devices in the driving circuit,  
 wherein the following are satisfied:  
 I. each of the first device-isolation portion not next to the photodiode and the second device-isolation portion has a structure comprising: 
 A. an electrically insulating film formed on a surface of the substrate so as to erode the substrate to a depth in a range of 1 nm to 50 nm, or  
 B. both an electrically insulating film formed on a surface of the substrate so as to erode the substrate to a depth in a range of 1 nm to 50 nm and an impurity diffusion region formed within the substrate, and  
 
 II. each of the first device-isolation portions next to the photodiode has a structure consisting of only an impurity diffusion region formed within the substrate directly under the substrate surface.  
 
     
     
       7. The camera according to  claim 6 , wherein the impurity diffusion region is formed by ion implantation. 
     
     
       8. The camera according to  claim 6 , wherein at least one part of the driving circuit is a dynamic circuit. 
     
     
       9. The camera according to  claim 6 , wherein the photodiode has a surface portion having a dark current inhibiting layer. 
     
     
       10. The camera according to  claim 6 , wherein the first device-isolation portion and the second device-isolation portion are formed by annealing in a hydrogen atmosphere. 
     
     
       11. A MOS (metal-oxide-semiconductor) image pick-up device comprising:
 a semiconductor substrate,  
 an imaging region formed on the semiconductor substrate by arraying plural unit pixels, and  
 a peripheral circuit region comprising a driving circuit for operating the imaging region formed on the semiconductor substrate;  
 where each of the unit pixels comprises: a photodiode, MOS transistors, and a first device-isolation potion, and  
 the peripheral circuit region comprises a second device-isolation portion for isolating devices in the driving circuit,  
 wherein the following are satisfied:  
 I. the first device-isolation portion has a structure comprising: 
 A. an electrically insulating film formed on a surface of the substrate so as to erode the substrate to a depth in a range of 1 nm to 50 nm, or  
 B. an impurity diffusion region formed within the substrate directly under the substrate surface, and  
 
 II. the first device-isolation portion and the second device-isolation portion have respective structures selected separately so as to be different from each other.  
 
     
     
       12. A MOS (metal-oxide-semiconductor) image pick-up device comprising:
 a semiconductor substrate,    an imaging region formed on the semiconductor substrate by arraying plural unit pixels, and    a peripheral circuit region comprising a driving circuit for operating the imaging region formed on the semiconductor substrate;    where each of the unit pixels comprises: a photodiode, MOS transistors, and a first device-isolation portion, and    the peripheral circuit region comprises a second device-isolation portion or isolating devices in the driving circuit,    wherein the following is satisfied:    the first device-isolation portion and the second device-isolating portion are selected separately from respective structures comprising: 
 A. an electrically insulating film formed on a surface of the substrate so as to erode the substrate to a depth in a range of 1 nm to 50 nm, or  
 B. an impurity diffusion region formed within the substrate directly under the substrate surface.  
   
     
     
       13. A camera comprising a MOS ( metal - oxide - semiconductor )  image pick - up device comprising:      a semiconductor substrate:        an imaging region formed on the semiconductor substrate by arraying plural unit pixels, and        a peripheral circuit region comprising a driving circuit for operating the imaging region formed on the semiconductor substrate;        where each of the unit pixels comprises: a photodiode, MOS transistors, and a first device - isolation portion, and        the peripheral circuit region comprises a second device - isolation portion for isolating devices in the driving circuit,        wherein the following is satisfied:        I. the first device - isolation portion has a structure comprising:      A. an electrically insulating film formed on a surface of the substrate so as to erode the substrate to a depth in a range of  1  nm to  50  nm, or        B. an impurity diffusion region formed within the substrate directly under the substrate surface, and          II. the first device - isolation portion and the second device - isolation portion have respective structures selected separately so as to be different from each other.