Freescale Semiconductor,inc.

Hernan A Reuda

Vishal P Trivedi

David Gareth Morgan

Wen Ling M Huang

Pamela J Welch

An improved varactor diode () having first () and second () terminals is obtained by providing a substrate () having a first surface () in which are formed isolation regions () separating first () and second () parts of the diode (). A varactor junction () is formed in the first part () and having a first side () coupled to the first terminal () and a second side () coupled to the second terminal () via a sub-isolation buried layer (SIBL) region () extending under the bottom () and partly up the sides () of the isolation regions () to a further doped region () ohmically connected to the second terminal (). The first part () does not extend to the SIBL region (). The varactor junction () desirably comprises a hyper-abrupt doped region (). The combination provides improved tuning ratio, operating frequency and breakdown voltage of the varactor diode () while still providing adequate Q.

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Phoenix, AZ, United States of America

Hernan A Reuda