Protection diode for improved ruggedness of a radio frequency power transistor and self-defining method to manufacture such protection diode
A semiconductor arrangement including:
a substrate having a substrate layer (13) with an upper and lower
surface, the substrate layer (13) being of a first conductivity type;
a first buried layer (12) in the substrate, extending along said
lower surface below a first portion of said upper surface of said substrate layer
(13), and a second buried layer (12) in the substrate, extending
along said lower surface below a second portion of said upper surface of said substrate
layer (13);
a first diffusion (26) in said first portion of said substrate
layer (13), being of a second conductivity type opposite to said first conductivity
type and having a first distance to said first buried layer (12) for defining
a first breakdown voltage between said first diffusion (26) and said first
buried layer (12);
a second diffusion (45) in said second portion of said substrate
layer (13), being of said second conductivity type and having a second distance
to said second buried layer (12) for defining a second breakdown voltage
between said second diffusion (45) and said second buried layer (12);
said first distance being larger than said second distance such that said first
breakdown voltage is larger than said second breakdown voltage.
