In-situ SiN_x/InN structures for InN field-effect transistors

摘要

Critical aspects of InN channel field-effect transistors (FETs) have been investigated. SiN_x dielectric layers were deposited in-situ, in the molecular beam epitaxy system, on the surface of 2 nm InN layers grown on GaN (0001) buffer layers. Metal-insulator-semiconductor Ni/SiN_x/InN capacitors were analyzed by capacitance-voltage (C-V) and current-voltage measurements and were used as gates in InN FET transistors (MISFETs). Comparison of the experimental C-V results with self-consistent Schroedinger-Poisson calculations indicates the presence of a positive charge at the SiN_x/InN interface of Q_(if)≈4.4-4.8 × 10~(13)cm~(-2), assuming complete InN strain relaxation. Operation of InN MISFETs was demonstrated, but their performance was limited by a catastrophic breakdown at drain-source voltages above 2.5-3.0 V, the low electron mobility, and high series resistances of the structures.