Demonstration of a silicon field-effect transistor using AlN as the gate dielectric

Abstract

As a precursor to cointegration of blue and ultraviolet light emitting nitrides with silicon microelectronics, an AlN on Si(111) metal-insulator-semiconductor field effect transistor has been fabricated and characterized. Current–voltage data show the threshold voltage and transconductance to be −0.8 V and 6 ms/mm, respectively, for a 50 nm insulator thickness. The ideal threshold voltage is 0.09 V. From the transconductance, a channel mobility of 45 cm2/V s is inferred. Capacitance versus voltage (C–V) measurements on a 210 nm film showed a flatband voltage of −4.2 V, corresponding to 8×1011 cm−2 trapped charges at the interface. Comparison of the experimental high-frequency (1 MHz) C–V plot to the theoretical plot indicates the presence of fast interface states. High-resolution transmission electron microscopy studies showed the AlN/Si(111) interface to be surprisingly well ordered in places, with the large lattice mismatch accommodated via a quasiperiodic array of misfit dislocations.