Hafnium-Silicon Schottky Barriers: Large Barrier Height on p-Type Silicon and Ohmic Behavior on n-Type Silicon

Abstract

Schottky‐barrier diodes of Hf on p‐type Si gave a height φ_MS = 0.90 eV, which is the largest value of φ_MS reported to date on Schottky barriers on either p‐ or n‐type Si. Excellent agreement was found between the φ_MS values determined from current‐voltage, activation energy, and capacitance‐voltage analyses. This large value of φ_MS of the Hf‐(p)‐Si Schottky barrier allows several new applications which were not possible before in the integrated circuit technology, such as clamping of p‐n‐p transistors and fabrication of enhancement‐mode p‐channel Schottky gate field‐effect transistors. Hafnium deposited on n‐type Si (N_D≅5×10¹⁵ cm⁻³) gave Ohmic behavior suggesting the validity of the work‐function‐difference model for the Hf–Si system. Under this assumption, the Schottky‐barrier analysis gives the work function of Hf=4.23±0.02 eV.