2018/06/08 by Sandeep Kumar, Himanshu Kumar, Sandeep Vura +6
Engineering · Materials Science · Physics and Astronomy · #Amorphous solid #Analytical Chemistry (journal) #Annealing (glass) #Crystallization #Dielectric #Ga2O3 and related materials #Gate dielectric #Semiconductor materials and devices #Semiconductor materials and interfaces #Sputter deposition #Sputtering #X-ray photoelectron spectroscopy #physics.app-ph
paper · pdf · doi:10.1109/ted.2019.2893288
arxiv created 2018/06/08 · openalex created_date 2018/06/13 · openalex publication_date 2019/01/25 · arxiv updated 2019/06/03 · openalex updated_date 2026/08/05
We report on the demonstration and investigation of Ta2O5as high-k dielectric for InAlN/GaN-MOS high-electron mobility transistor (HEMT)-on-Si. Ta2O5of thickness 24 nm and dielectric constant ~30 was sputter deposited on InAlN/GaN HEMT and was investigated for different post deposition anneal (PDA) conditions. The gate leakage was 16 nA/mm at -15 V which was ~five orders of magnitude lower compared to reference HEMT. The 2-D electron gas (2-DEG) density was found to vary with annealing temperature suggesting the presence of net charge at the Ta2O5/InAlN interface. Dispersion in the capacitance-voltage (C-V) characteristics was used to estimate the frequency-dependent interface charge, while energy band diagrams under flat band conditions were investigated to estimate fixed charge. The optimum anneal condition was found to be 500 °C which has resulted into a flat band voltage spread (ΔVFB) of 0.4 V and interface fix charge (Qf) of 3.98 × 1013cm-2. X-ray photoelectron spectroscopy spectra of as-deposited and annealed Ta2O5film were analyzed for Ta and O compositions in the film. The sample annealed at 500 °C has shown Ta:O ratio of 0.41. X-ray diffraction analysis was done to check the crystallization of amorphous Ta2O5film at higher annealing temperatures.