Abstract: The paper contrasted CB junction reverse leak currents I_cbo and electronic noise spectrums S_vcb(f) of color TV high frequency video transistors(2688B, 2688S, 2688) produced by three kinds of techniques. Its discussed that interface state and surface movable charge cause surface leak current, which make devices produce electronic noise and affect other parameters such as reverse breakdown voltage and small current amplif ying coefficient. The experiment showed that surface leak current can be controlled, transistor electronic noise can be lowered and the reliability, stability and life can be enhanced by adopting surface passivation technique.

Key words: noise, reliability, transistor