Impact of Charge Trapping on Epitaxial p-Ge-on-p-Si and HfO2Based Al/HfO2/p-Ge-on-p-Si/Al Structures Using Kelvin Probe Force Microscopy and Constant Voltage Stress

Choudhary S, Schwarz D, Funk HS, Khosla R, Sharma SK, Schulze J (2021)

Publication Type: Journal article

Publication year: 2021

Journal

IEEE Transactions on Nanotechnology Institute of Electrical and Electronics Engineers (IEEE)

Book Volume: 20

Pages Range: 346-355

Article Number: 9390309

DOI: 10.1109/TNANO.2021.3069820

Abstract

The quest for the high speed, low power digital logic circuits urge an imperative demand of compatible high-κ dielectric integration on novel Germanium (Ge) based channel material. Here, first ever a methodical nanoscopic and microscopic probes were attempted to Atomic Layer Deposited, Hafnium Dioxide (HfO2) dielectrics on Molecular Beam Epitaxy (MBE) of p-Ge-on-p-Si stack. Kelvin Probe Force Microscopy based contact potential difference (CPD) analysis reveals that the disintegration of trapped charges lasting for ∼18 hours. The impact of constant voltage stress (CVS) on trapped charges results in variation of threshold voltage (Vth) and hysteresis window (W) were studied. The cyclic Capacitance-Voltage (C-V) characteristics at 0.5 MHz exhibit the shift in the flat band (ΔVfb), ΔVth, and ΔW at 10V stress were ∼0.84V, ∼0.62V, and ∼0.47V, respectively. While the computed interface trap density (Dit) and total effective charge density (Qeff) were ∼8.49 × 1012 eV-1cm-2 and ∼1.81 × 1012 cm-2, respectively. The gate leakage current density, (J) at 5V is 26.53 × 10-6 A/cm2 and reduced by a factor of ∼6.8 after 10V, CVS. Whereas the current density (J) increases from ∼26.53 × 10-6 A/cm2 at 25 °C by a factor of ∼2 at 125 °C. To study the retention and effect of charge trapping, the stress-time analysis was performed for 8000s at 3V (CVS). The r.m.s. surface roughness of HfO2 thin films was found to be ∼0.23 nm. X-ray photoelectron spectroscopy (XPS) depth profiling categorized the elemental composition of thin films. These investigations would help to HfO2/p-Ge-on-p-Si system interfacial engineering well before the Ge based nano device realization.

Authors with CRIS profile

Jörg Schulze

Involved external institutions

Indian Institute of Technology IIT Mandi IN India (IN) Universität Stuttgart DE Germany (DE)

How to cite

APA:

Choudhary, S., Schwarz, D., Funk, H.S., Khosla, R., Sharma, S.K., & Schulze, J. (2021). Impact of Charge Trapping on Epitaxial p-Ge-on-p-Si and HfO2Based Al/HfO2/p-Ge-on-p-Si/Al Structures Using Kelvin Probe Force Microscopy and Constant Voltage Stress. IEEE Transactions on Nanotechnology, 20, 346-355. https://doi.org/10.1109/TNANO.2021.3069820

MLA:

Choudhary, Sumit, et al. "Impact of Charge Trapping on Epitaxial p-Ge-on-p-Si and HfO2Based Al/HfO2/p-Ge-on-p-Si/Al Structures Using Kelvin Probe Force Microscopy and Constant Voltage Stress." IEEE Transactions on Nanotechnology 20 (2021): 346-355.

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