Andrea Candelori

We studied the response of a commercial 0.13-μm CMOS technology to high-energy (24-GeV) proton irradiation, which emulated the environment the front-end electronics of future high energy accelerators will have to operate in, for fluences up to 10 ¹⁶ p/cm ² . After irradiation, large negative shifts in the threshold voltage and large drops in the maximum transconductance were observed in PMOSFETs, whereas comparatively smaller effects were present in NMOSFETs. Furthermore, both kinds of devices exhibited an increase in the drain off-current and in the gate leakage current. All the observed effects were roughly proportional to the proton fluence. For PMOSFETs only, the amount of the degradation depended on the device channel length. The changes in the characteristics of the irradiated devices were attributed to the build-up of positive charge in the LDD spacer oxide and to the creation of defects in the gate oxide.

The main DC and AC characteristics of AC-coupled polysilicon-biased silicon microstrip detectors have been measured in order to determine the set of SPICE parameters of these devices based on a RC network. For this purpose each strip has been divided in 200 unit cells and simulations with 5 and 9 strips have been performed. The model is capable of calculating the interstrip and coupling impedance and phase angle in good agreement with experimental results up to a frequency of 1 MHz. The electrical propagation of a current signal simulating the charge pulse of a ionising particle along the strips has been studied. The role of the input characteristics of the read-out electronics on the detector output signals has been addressed. The signal propagation has been studied also for anomalous working conditions of the detector, such as a strip with a break in the A1 film, or disconnected from the read-out electronics