Προσομοίωση, κατασκευή και χαρακτηρισμός διόδων p-i-n από 4H-SiC για μικροκυματικές εφαρμογές ισχύος
Conception, realisation et caracterisation de diodes pin en Carbure de Silicium (SiC) pour applications micro-ondes de puissance
P-i-n diodes are widely used UHF discrete semiconductor diode components. UHF power switching devices based on p-i-n diodes are basic components of complex communication systems, discrete phase shifters, pulse modulators and active protectors. The capability of handling high power loads and of switching high voltage signals is the most important characteristic of switching devices for a number of applications, for example, in active protectors of complex transceiver systems, UHF ovens with rotating field and microwave sources of electron. Currently, tube devices or multi-diode switches are used to handle these large power loads since silicon p-i-n diodes can only switch microwave power up to few kW (pulsed). A wide bandgap (3ev), a high critical field (3MV/cm), as good thermal conductivity (3 to 5 times higher than Silicium) allow to think SiC as the best potential candidate for high temperature, high power and high frequency applications. 4H-SiC p-i-n diodes were designed, fabricated and characterized for use in microwave applications. The diodes with mesa structure diameters between 80 and 150μm, exhibited a blocking voltage of 1100V, a 100 mA differential resistance of 1-2 , a capacitance below 0.5pF at a punch through voltage of about 100V and a carrier effective lifetime between 15-27 ns. X-band microwave switches based on 4H-SiC p0i-n diodes are demonstrated for the first time. The switches exhibited insertion loss as low as 0.7 db, isolation up to 25 dB and were able to handle microwave power up to 2kW at 10GHz.