Abstract Disclosed is a low temperature technique for annealing implantation damage and activating dopants. Conventional furnace annealing requires temperatures as high as 1000 DEG to 1100 DEG C. to completely anneal the dopant implantation damage; 75 KeV arsenic implantation followed by 550 DEG C. for 75 minutes and 900 DEG C. for 30 minutes in nitrogen for instance is not sufficient to anneal the implantation damage and results in a leakage current of the order of 1 mA per cm2. If, however, subsequent to the arsenic implantation, 0.4 KeV hydrogen ions are implanted using a Kaufman ion source with an accelerator current of 200 milliamp, then only 500 DEG to 600 DEG C. for one hour anneal in nitrogen is sufficient to eliminate the arsenic implantation damage. This results in a leakage current of the order of 5 to 25 nA per cm2 and a complete dopant activation is achieved.
A method of low temperature annealing of a silicon semiconductor that has been doped by ion implantation with an element selected from the group consisting of arsenic and phosphorous, said method comprising: ion beam implantation of hydrogen ions subsequent to and in the same area as the element selected from the above group that has been implanted, and annealing the semiconductor at a temperature between about 500° C. and about 600° C. for a time of about one hour in an inert atmosphere.
Claim 2
Independent Claim
83 words
A method of low temperature annealing of a silicon semiconductor that has been doped by ion implantation with an element selected from the group consisting of arsenic and phosphorous, said method comprising: ion beam implantation of hydrogen ions subsequent to and in the same area as the element selected from the above group that has been implanted, and annealing the semiconductor at a temperature between about 500° C. and about 600° C. for a time of about one hour in an inert atmosphere.
Claim 3
Dependent Claim
16 words
The process of claim 1 wherein the hydrogen ions are supplied by a Kaufman ion source.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein said silicon semiconductor has a shallow junction of ≦0.1 μm.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein said silicon semiconductor has been doped with about 70 to 75 KeV, 4×10 15 cm -2 arsenic.
Claim 6
Dependent Claim
11 words
The method of claim 1 wherein said inert atmosphere comprises nitrogen.
Claim 7
Dependent Claim
11 words
The method of claim 1 wherein said inert atmosphere comprises argon.
Claim 8
Dependent Claim
21 words
The method of claim 1 wherein hydrogen ions are implanted with a current density of about 10 -3 amps/cm 2 .
Claim 9
Dependent Claim
22 words
The method of claim 1 wherein the hydrogen ions implanted have an energy of between about 0.4 KeV and about 1.4 KeV.
Claim 10
Dependent Claim
21 words
The method of claim 1 wherein the annealing temperature is about 500° C. and the annealing time is about one hour.
Claim 11
Dependent Claim
12 words
The method of claim 1 wherein said semiconductor is a photovoltaic cell.
Claim 12
Dependent Claim
15 words
The method of claim 10 wherein said semiconductor is a dendritic web silicon photovoltaic cell.