Sputtered thin film transistors (TFTs), which were hydrogenated and fluorinated by ion implantation, were exposed to gamma irradiation up to 2500 Gy. Long term post-irradiation stability of TFTs was studied after eight months of storage and under positive bias test at 150 °C in time intervals of 1–10 h. The effects induced by irradiation and during relaxation period were monitored by current–voltage (I–V) measurements. I–V data were used to determine post-irradiation changes in different TFT parameters, such as threshold voltage, interface states density and grain boundaries trap density. The behaviour of these parameters was compared for four types of TFTs: non-fluorinated-hydrogenated, fluorinated, hydrogenated and fluorinated-hydrogenated, and it was found that hydrogenated TFTs showed greater instability. A mechanism for grain boundary traps generation is proposed.

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An impulse radio ultra-wideband (IR-UWB) transmitter (TX) consuming ultra-low power is presented. The lowcomplexity topology features control of the power spectral density (PSD) and central frequency for a broad range of applications. The PSD and frequency adjustment are accomplished by employing a tunable pulse generator and an adjustable driver. The IR-UWB TX suitable for on-off keying coding is fabricated in a low-cost 180 nm UMC CMOS technology and occupies the total die area of 0.63 mm 2. The measurement results show the transmitter output swing of 320 mVpp (peak-topeak amplitude) with the pulse duration of 0.6 ns, and the spectrum covering the frequency range from 3 to 7.5 GHz. The total DC power consumption is 1 mW resulting in energy consumption of 5 pJ/pulse at 200 MHz data rate.

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