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Solid-state varactor performance is evaluated in light of fundamental tradeoffs imposed by semiconductor material. This leads to the important conclusion that the product of Q factor, frequency, tuning range, and breakdown voltage has an upper limit (between 5 and 40 THzmiddotV for silicon) that is dictated primarily by semiconductor material parameters, and to a lesser degree on doping level and temperature. This limit is then approached by experimental hyperabrupt profiles with a product of 17 THzmiddotV that were fabricated in a SiGe BiCMOS process. Two complementary analysis techniques based on LCR and high-frequency measurements are presented

An industrial SiGe BiCMOS technology is presented, in which the silicon substrate has been removed and replaced by a lossless glass substrate. This will enable the integration of better passives, while the active devices remain fully library compatible. Specifically, ideal NPN characteristics with 111/94 GHz f/sub T//f/sub max/ are shown without significant degradation of the thermal characteristics. This substrate transfer technology requires almost no changes to the standard processing and gives access to high-performance inverse NPN and vertical PNP devices, in addition to the lossless substrate.

This paper reports on the power performance of RF high-breakdown voltage (>16.5 V) SiGeC HBT power devices, which have been successfully integrated into a BiCMOS platform featuring 0.25 /spl mu/m CMOS and a full set of high-quality passives. These devices have an excellent tradeoff between power gain and breakdown voltage. The high speed combined with low parasitic elements enables over 80% power-added efficiency (PAE) and corresponding power gains (G/sub p/) of 18 dB and higher over a relatively wide range of power densities. A peak performance of 88% PAE and 20 dB G/sub p/ is obtained at 0.25 W continuous-wave output power with a 792 /spl mu/m emitter length device (396 /spl mu/m/sup 2/ emitter area) operating at 1.8 GHz with 3.3 V supply voltage. Excellent power scaling versus emitter area is obtained. Measured output power shows an ideal increase of 3 dB when doubling the area. Also the corresponding matching scales. This is achieved by minimizing parasitic elements using deep trench isolation and careful design of the metal wiring. Furthermore, the base and emitter doping profiles are tuned to minimize the temperature dependence of the power gain. In combination with the high PAE, no effect of self-heating on power scaling is found.