CONTACTLESS MEASUREMENT OF ELECTRON-MOBILITY IN FERROELECTRIC GATE HIGH-ELECTRON-MOBILITY TRANSISTOR STRUCTURES

We have evaluated the electron mobility in BaMgF4/AlGaAs/GaAs(100) hig h-electron-mobility transistor (HEMT) structures using a contactless m obility measurement system. It has been found that the HEMT structure can be prevented from deteriorating when the BaMgF4 layer is properly deposited, and that dependence of the electron mobility on the N-AlGaA s layer thickness is explained using a simple parallel conduction theo ry. It has also been found that the electron mobility in the structure s is decreased from 6300 cm(2)/(V s) to 3300 cm(2)/ (V . s) at room te mperature as the BaMgF4 growth temperature is increased from 550 degre es C to 650 degrees C.