what is single side junction?

[llbaobao]

Sometimes I found in bipolar process, there are "single side junction".

But I do not know what is single side junction, Can anyone tell me ? or give me some link to explain this?

Thanks very much!

 

[dick_freebird]

It may be talking about a junction with extremely
high doping ratio, like a base at 1E17 and emitter at
1E20 N/cm3; high ratios favor emitter injection
efficiency. And of course the emitter has only one
"side" junction-wise, but I don't think that's the point.

 

[llbaobao]

thanks, i will go forward this issue.