ELECTRICAL-PROPERTIES OF FERROELECTRIC GATE HEMT STRUCTURES

Electrical properties of ferroelectric BaMgF4 films grown on AlGaAs/Ga As(100) high-electron-mobility transistor (HEMT) structures are invest igated. It is shown that a spontaneous polarization of 1.3 mu C/cm(2) and a coercive field of 200 kV/cm are obtained from polarization vs el ectric field (P-E) hysteresis measurements for mainly (140)-oriented B aMgF4 films. In addition, a threshold shift (memory window) as large a s 1.2 V is demonstrated in capacitance-voltage (C-V) hysteresis measur ements for a BaMgF4(140)/HEMT structure in which the growth temperatur e of the BaMgF4 film is about 550 degrees C. This work indicates that the suitable growth temperature of BaMgF4 films on the HEMT structure is 550 degrees C.