Contact and Channel 3rd-Order Nonlinearity in III-N HFETs

III-nitride microwave control devices and ICs

“…The hybrid resistor-diode-transistor model built to validate this concept demonstrated the third intermodulation power reduction by more than 30 dB [24]. In this demonstration, the nonlinear ohmic contact was modeled as a diode-resistor combination [23,24] (figure 9).…”

“…The intermodulation distortions in III-nitride HFETs have been analyzed in [22,23]. The obtained results show that these devices are potential candidates for very high-linearity components with the IP3 points in the range of 70-100 dBm, as illustrated in figure 8 [23].…”

“…The distortion mechanisms leading to the nonlinearities in pin diode, GaAs MESFET and RF MEMS devices have been discussed in detail in [19][20][21]. The intermodulation distortions in III-nitride HFETs have been analyzed in [22,23]. The obtained results show that these devices are potential candidates for very high-linearity components with the IP3 points in the range of 70-100 dBm, as illustrated in figure 8 [23].…”

“…In relatively shortchannel devices used for RF switching, with the sourcedrain distance less than 5 μm, the contact resistance may constitute 25-50% of the total device resistance. As shown in [23,24], under typical switching RF drive conditions the contact and channel nonlinearity coefficients for GaN HFETs have opposite signs. Therefore, with proper design, contact and channel linearity may compensate for each other resulting in much lower level of third-order distortions.…”