Characterization and High‐Frequency Applications of Barium Antimonide Thin Films for Voltage‐Controlled Negative Capacitance and 6G Technology

Abstract

Herein, films of barium antimonides (BaSb) are fabricated by a thermal deposition technique under a vacuum pressure of 10−5 mbar. BaSb films exhibit orthorhombic lattice. Over a wide range of scans, the films are mostly stoichiometric, displaying atomic contents of 50.17 and 49.83 at% for Ba and Sb, respectively. Morphological analyses of these films show the growth of large grains with sizes ranging from 1.64 to 4.14 μm. Dynamic electrical measurements on Ag/BaSb/Ag films are conducted in the frequency domain of 0.01–1.80 GHz. The films display features of voltage‐controlled negative capacitance source (VCNC) and resonance–antiresonance peaks at a critical frequency of 1.64 GHz. Lorentz models spectral analyses on these peaks indicate that they correspond to a high‐frequency capacitance value of 2.8 nF, a density of oscillators of 4 × 1010 cm−3, and a scattering time constant of τ = 100 ns. Additionally, Ag/BaSb/Ag films show a wide variety in the cutoff frequency spectra, making them suitable for high‐frequency applications. The cutoff frequency varies from 2.6 GHz to 1.0 THz as driving frequency increases from 1.0 to 1.64 GHz. The features of VCNC sources, resonance–antiresonance behavior, and high cutoff frequency make BaSb thin films promising for thin‐film transistors and 6 G technology applications.