Synergistic Boron Doping of Semiconductor and Dielectric Layers for High-Performance Metal Oxide Transistors: Interplay of Experiment and Theory

We report the results of a study to enhance metal oxide (MO) thin-film transistor (TFT) performance by doping both the semiconductor (In₂O₃) and gate dielectric (Al₂O₃) layers with boron (yielding IBO and ABO, respectively) and provide the first quantitative analysis of how B doping affects charge transport in these MO dielectric and semiconducting matrices. The impact of 1-9 atom % B doping on MO microstructure, morphology, oxygen defects, charge transport, and dielectric properties is analyzed together, in detail, by complementary experimental (microstructural, electrical) and theoretical (ab initio MD, DFT) methods. The results indicate that B doping frustrates In₂O₃ crystallization while suppressing defects responsible for electron trapping and carrier generation. In the adjacent Al₂O₃ dielectric, B doping increases the dielectric constant and refractive index while reducing leakage currents. Furthermore, optimized solution-processed TFTs combining IBO channels with 6 atom % B and ABO dielectrics with 10 atom % B exhibit field effect mobilities as high as 11 cm² V^-1 s^-1, current on/off ratios >10⁵, threshold voltages = 0.6 V, and superior bias stress durability.