Novel varactors in BiCMOS technology with improved characteristics

The first true BiCMOS varactor combining typical elements of CMOS and bipolar Technologies is presented. Several test structures and different versions have been manufactured in a 0.25 /spl mu/m BiCMOS technology and measured. The first type of the proposed novel varactor structure features a capacitance tuning range (ratio of maximum to minimum achievable values) C/sub max//C/sub min/ of 3.8:1 with a minimum quality factor Q of 32 and a maximum Q of 273. Choosing the second type of the herein presented novel device, allows quality factors from 6 to above 500, while increasing the capacitance tuning range to an outstanding value of 10.11:1.