Radiation tolerance of SiGe BiCMOS monolithic silicon pixel detectors without internal gain layer

A monolithic silicon pixel prototype produced for the MONOLITH ERC Advanced project was irradiated with 70 MeV protons up to a fluence of 1 x 10(16)1 MeV n(eq)/cm(2). The ASIC contains a matrix of hexagonal pixels with 100 mu m pitch, readout by low-noise and very fast SiGe HBT frontend electronics. Wafers with 50 mu m thick epilayer with a resistivity of 350 Omega cm were used to produce a fully depleted sensor. Laboratory tests conducted with a(90)Sr source show that the detector works satisfactorily after irradiation. The signal-to-noise ratio is not seen to change up to fluence of 6 x 10(14)n(eq)/cm(2). The signal time jitter was estimated as the ratio between the voltage noise and the signal slope at threshold. At -35 degrees C, sensor bias voltage of 200 V and frontend power consumption of 0.9 W/cm(2), the time jitter of the most-probable signal amplitude was estimated to be sigma Sr-90(t) = 21 ps for proton fluence up to 6 x 10(14)n(eq)/cm(2) and 57 ps at 1 x 10(16)n(eq)/cm(2). Increasing the sensor bias to 250 V and the analog voltage of the preamplifier from 1.8 to 2.0 V provides a time jitter of 40 ps at 1 x 10(16)n(eq)/cm(2).