Intermodulation distortion of low noise silicon BJT and MOSFET fabricated in BiCMOS process

Even though BiCMOS process has an ability to make both BJT and MOSFET on si ngle-chip, only BJT has been used for BiCMOS Si-MMIC LNA because of its low noise and high gain performance under low d.c. supply power. But the disto rtion performance of BJT should be improved for the receiver applications i n some wireless systems. In this paper, intermodulation distortion characte ristics comparison is carried out between BJT and MOSFET fabricated in the same BiCMOS process by the analysis based on the simplified transistor mode ls with extracted device parameters. The analytical result shows that MOSFE T has lower intermodulation distortion characteristics compared with BJT, a nd the result is evaluated by the measurements. In order to obtain both low distortion and low noise characteristics, a two-stage Si-MMIC LNA is devel oped by using BJT as the Ist stage and MOSFET as the 2nd stage of LNA. The fabricated LNA performs NF of 2.45 dB, gain of 19.3 dB, IIP3 of -14.6 dBm a nd OIP3 of +4.7 dBm under 3 V/7.2 mA d.c. supply power.