This brief presents an energy-efficient level shifter (LS) able to convert extremely low level input voltages to the nominal voltage domain. To obtain low static power consumption, the proposed architecture is based on the single-stage differential-cascode-voltage-switch scheme. Moreover, it exploits self-adapting pull-up networks to increase the switching speed and to reduce the dynamic energy consumption, while a split input inverting buffer is used as the output stage to further improve energy efficiency. When implemented in a commercial 180-nm CMOS process, the proposed design can up-convert from the deep subthreshold regime (sub-100 mV) to the nominal supply voltage (1.8 V). For the target voltage level conversion from 0.4 to 1.8 V, our LS exhibits an average propagation delay of 31.7 ns, an average static power of less than 60 pW, and an energy per transition of 173 fJ, as experimentally measured across the test chips.

A high-performance temperature sensor based on coupled 4H-SiC Schottky diodes is presented. The linear dependence on temperature of the difference between the forward voltages appearing on two diodes biased at different constant currents, in a range from 30 °C up to 300 °C, was used for temperature sensing. A high sensitivity of 5.11 mV/°C was measured. This is, to the best of our knowledge, the first experimental result about a proportional-to-absolute-temperature sensor made with SiC diodes, showing both a good degree of linearity and long-term stability performance.

The performance of a 4H-SiC Schottky diode for thermal sensing in the wide temperature range from T = 85 up to 443 K is presented. The linear dependence on temperature of the forward voltage drop, for different bias currents, is investigated through an analytical study of the temperature-dependent physical Schottky diode parameters. A high sensitivity of 1.18 mV/K was observed for a constant bias current of I _D = 80 μA. The device exhibits a good degree of linearity with a calculated root mean square error, with respect to the best-linear fitting model, lower than 2.7 mV. Moreover, the proposed sensor shows a good repeatability maintaining a stable output over more cycles of measurements, from (down to) 85 up to (from) 443 K, in a long period of time.

The linear dependence on temperature of the voltage drop V_D across a forward-biased 4H-SiC p-i-n diode is investigated experimentally. The results show that the fabricated temperature sensor has a high degree of linearity in the range from room temperature up to 573 K corresponding to a root-mean-square error lower than 0.5%. A maximum sensitivity of 2.66 mV/K was calculated. The low saturation current of the p-i-n diode, well below the forward biasing current also at high temperatures, reduces the nonlinear effects in the V_D-T characteristic allowing the design and fabrication of highly linear sensors operating in a wider temperature range.

Silicon photonics is a new emerging and disruptive technology aimed at using cost-effective silicon-based materials for the generation, control, and detection of modulated light signals for optical communication. Hydrogenated amorphous silicon (a-Si:H) is a particularly promising platform for enabling the desired matching between electronics and on-chip photonics. Thin a-Si:H layers can be in fact deposited using the CMOS-compatible low-temperature plasma-enhanced chemical vapor deposition technique, with no impact at all on the microelectronic layers. This paper provides an overview of the progress and the state of the art of a-Si:H-based active photonic devices, focusing, in particular, on the low technological complexity required for an easy integration within a single photonic microchip. This paper consists of three main sections, in each of which the exploitable optoelectronic effects present in a-Si:H are presented. A comparison between some experimental a-Si:H and crystalline-Si photonic components available in the literature is presented.

The linear dependence on temperature of the voltage drop difference measured on two diodes biased at different constant currents has been characterized in a range from room temperature up to 573 K. The realized proportional to absolute temperature sensor shows a good level of linearity and the corresponding rms error lower than 0.3%. Moreover, a maximum sensitivity of 610 μV/K has been obtained, with an extrapolated output converging to 0 V at T = 0 K, in agreement with theory and allowing a single-point temperature calibration.