Process for forming low defect density heterojunctions

Abstract

A method for forming a low defect density heterojunction between a first and a second compound, the first and second compounds each includes a group III element combined with a group V element in the periodic table, the method includes the steps of introducing in the deposition chamber the flux of the group III element for the first compound at substantially the same time while introducing in the deposition chamber a flux of the group V element for the second compound, stopping the flux of the group III element for the first compound after a first predetermined time period, stopping the flux of the group V element for the first compound after a second predetermined time period, and introducing in the deposition chamber a flux of the group III element the group V element for the second compound.

1 . A method for forming a low defect density heterojunction between a first compound and a second compound, the first and second compounds each including a group III element and a group V element in the periodic table, the method comprising:
 simultaneously depositing a first group III element and a first group V element to form a first compound layer including the first compound during a first period of time;   continuously depositing the first group V element while stopping the depositing of the first group III element to form a first junction surface substantially covering the first compound layer during a second period of time, the first junction surface including the first group V element and substantially free of the first group III element; and   simultaneously depositing a second group III element and a second group V element to form a second junction surface and a second compound layer including the second compound during a third period of time, the second junction surface substantially covering the first junction surface, the second compound layer formed on the second junction surface, such that the first and second junction surfaces combine to form the low defect density heterojunction.   
     
     
         2 . The method of  claim 1 , wherein the first group III element is indium (In). 
     
     
         3 . The method of  claim 1 , wherein the second group V element is antimony (Sb). 
     
     
         4 . The method of  claim 1 , wherein the first group V element is arsenic (As). 
     
     
         5 . The method of  claim 1 , wherein the second group III element is selected from a group consisting of aluminum (Al), gallium (Ga), and combinations thereof. 
     
     
         6 . The method of  claim 1 , wherein the first group V element is chemically bonded to the first group III element to form the first compound, and wherein the second group V element is chemically bonded to the second group III element to form the second compound. 
     
     
         7 . The method of  claim 1 , wherein the second period of time comes after the first period of time, and the third period of time comes after the second period of time. 
     
     
         8 . The method of  claim 1 , wherein the second junction surface consists essentially of the second group III element. 
     
     
         9 . The method of  claim 1 , wherein the first group III element is different from the second group III element, and wherein the first group V element is different from the second group V element. 
     
     
         10 . A method for forming a low defect density heterojunction between a first compound and a second compound, the first and second compounds each including a group III element and a group V element in the periodic table, the method comprising:
 simultaneously introducing a first flux of a first group III element and a second flux of a first group V element to form a first compound layer including the first compound;   stopping the first flux of the first group III element while continuing the second flux of the first group V element to form a first junction surface substantially covering the first group III element of the first compound layer; and   stopping the second flux of the first group V element while introducing a third flux of a second group III element and a fourth flux of a second group V element to form a second junction surface and a second compound layer including the second compound.   
     
     
         11 . The method of  claim 10 , wherein the second junction surface substantially covers the first junction surface, and the second compound layer is formed on the second junction surface, such that the first and second junction surfaces combine to form the low defect density heteroj unction. 
     
     
         12 . The method of  claim 10 , wherein the first group III element is indium (In) and the first group V element is arsenic (As). 
     
     
         13 . The method of  claim 10 , wherein second group V element is antimony (Sb), and the second group III element consists of an element selected from a group consisting of aluminum (Al), gallium (Ga), and combinations thereof. 
     
     
         14 . The method of  claim 10 , wherein the second junction surface consists essentially of the second group III element. 
     
     
         15 . The method of  claim 10 , wherein the first group III element is different from the second group III element, and wherein the first group V element is different from the second group V element. 
     
     
         16 . The method of  claim 10 , further comprising:
 stopping the third flux of the second group III element and the fourth flux of the second group V element.   
     
     
         17 . A method for forming a low defect density heterojunction, the method comprising:
 concurrently introducing a first flux of indium (In) and a second flux of arsenic (As) to form an indium arsenic (InAs) compound layer during a first period of time;   introducing only the second flux of arsenic (As) to form a first junction surface directly on the indium arsenic (InAs) compound layer during a second period of time; and   concurrently introducing a third flux of gallium (Ga), a fourth flux of aluminum (Al), and a fifth flux of antimony (Sb) to form a second junction surface directly on the first junction surface and to form an aluminum gallium antimonide (AlGaSb) compound layer on the second junction surface during a third period of time, the second junction surface having a relationship with the first junction surface to form the low defect density heterojunction between the indium arsenic (InAs) compound layer and the aluminum gallium antimonide (AlGaSb) compound layer.   
     
     
         18 . The device of  claim 17 , wherein the first period of time occurs immediately before the second period of time and the second period of time occurs immediate before the third period of time. 
     
     
         19 . The device of  claim 17 , wherein the relationship between the first junction surface and the second junction surface includes a chemical relationship, such that the first junction surface partially interposes with the second junction surface. 
     
     
         20 . The device of  claim 17 , further comprising:
 stopping the first flux of indium (In) during the second period of time; and   stopping the second flux of arsenic (As) during the third period of time.