A BICMOS process is presented that includes an ultra-low capacitance NPN bipolar transistor (PRET) together with conventional 10 GHz single-poly NPN and MOS devices. Isolation is done using shallow (STI) and deep trenches. The mechanism of capacitance reduction by STI is discussed. The PRET concept, with a 0.2 μm-wide emitter is shown to yield record low capacitances (emitter/base: 1.5 fF, collector/base: 1 fF) combined with high-frequency capability (the cut-off frequency is 14 GHz). This concept is demonstrated in a 2 GHz low-noise amplifier. Proper functioning is obtained at a 3 times lower power consumption than previously reported in literature.