Question

The major disadvantage of PN-junction isolation technique is:

(a) Formation of Parasitic Resistance

(b) Formation of Parasitic Capacitance

(c) Formation of Isolation island

(d) None of the mentioned

I got this question by my college director while I was bunking the class.

The origin of the question is Basic Planar Process topic in section IC Fabrication of Linear Integrated Circuits

Answer 1

The accurate option is (b) Formation of Parasitic Capacitance

Get the lowdown with: The presence of Parasitic Capacitance at the isolating PN-junction, results in an inevitable capacitor coupling between the component and substrate. This also limits the performance of circuit at high frequencies.