johnuk
Electrical
- May 20, 2005
- 2
Hi,
I'm very new to semiconductor theory so I wanted to ask if anyone might be able to help with two questions I have.
Firstly, I've see a few documents that have mentioned N layers being composed of both N- and N+ regions. Why do manufacturers use two layers and what is it exactly that causes the difference between the two? Different doping perhaps?
Secondly, I've been trying to find out as much as I can about soft recovery diodes. So far I've discovered they used to be doped with heavy metals. And that the newer patents are for techniques using H+ and electron irradiation. I read one article describing the use of Helium implantation but I am assuming by Helium implanting they likely meant Helium nucleus implanting; proton implanting.
The documents I've found are a bit too detailed for me to keep up with, they assume I already have quite a detailed understanding of the theory. Would anyone be able to explain in a simpler way what is done to lower the reverse recovery snap off. I know it has something to do with reducing carrier densities in purposefully generated trench like defects on the wafer. Also, is there an opposite to this characteristic? A soft peak. A method by which the device would be made to softly approach it's peak current rather than rushing hard against it's maximum?
I'd really appreciate any help you can provide with this!
Many thanks!
John
I'm very new to semiconductor theory so I wanted to ask if anyone might be able to help with two questions I have.
Firstly, I've see a few documents that have mentioned N layers being composed of both N- and N+ regions. Why do manufacturers use two layers and what is it exactly that causes the difference between the two? Different doping perhaps?
Secondly, I've been trying to find out as much as I can about soft recovery diodes. So far I've discovered they used to be doped with heavy metals. And that the newer patents are for techniques using H+ and electron irradiation. I read one article describing the use of Helium implantation but I am assuming by Helium implanting they likely meant Helium nucleus implanting; proton implanting.
The documents I've found are a bit too detailed for me to keep up with, they assume I already have quite a detailed understanding of the theory. Would anyone be able to explain in a simpler way what is done to lower the reverse recovery snap off. I know it has something to do with reducing carrier densities in purposefully generated trench like defects on the wafer. Also, is there an opposite to this characteristic? A soft peak. A method by which the device would be made to softly approach it's peak current rather than rushing hard against it's maximum?
I'd really appreciate any help you can provide with this!
Many thanks!
John
