MOS capacitors with ultrathin (≅1.2 nm) oxide grown by different techniques have been fabricated on Strained Si/Relaxed SiGe/n-Si substrates with linearly graded SiGe. These techniques involve thermal oxidation, chemical oxidation and both followed by anodic oxidation. Significant improvement in interface states has been obtained when oxidation was followed by anodic oxidation. The leakage currents and reliability characteristics have also shown great improvement. Band gap offsets extracted using a simple and novel technique are found to match well with expected values. © 2007 IEEE.

Amitava Dasgupta

Department of Electrical Engineering

Nandita Dasgupta

Gates (transistor)

Leakage currents

Microelectronics

MOS capacitors

MOSFET devices

reliability

Semiconducting silicon

Band gaps

CHEMICAL OXIDATIONS

Expected values

Interface state

LOW TEMPERATURE TECHNIQUES

Novel techniques

RELIABILITY CHARACTERISTICS

Si substrates

Strained Silicon

Strained-Si

THERMAL OXIDATIONS

Ultra-thin oxides

ULTRATHIN GATE OXIDE

Anodic oxidation

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IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Novel low temperature techniques for growth of ultrathin oxides for strained Si MOS devices

Proceedings of the International Conference on Microelectronics, ICM

The presence of weak spots and pinholes in ultrathin gate oxides significantly increases the leakage current, thereby degrading the device performance. This paper proposes a method, which identifies the weak spots in thermally grown gate oxide and repairs them by selective anodization. By controlling the applied voltage, it is ensured that current flows only through the weak spots in the oxide during anodization. Anodic oxide therefore grows over these weak spots, improving the reliability of the oxide without increasing the gate oxide thickness. Significant improvement in electrical characteristics was observed in the gate oxides treated by anodic oxidation.

IEEE Electron Device Letters

Improvement in electrical characteristics of ultrathin thermally grown SiO2 by selective anodic oxidation

IEEE Transactions on Electron Devices

Determination of deep ultrathin equivalent oxide thickness (EOT) from measuring flat-band C-V curve

Strained Silicon Heterostructures: materials and devices

Deep submicron CMOS based on silicon germanium technology

Solid-State Electronics

New technique for the characterization of Si/SiGe layers using heterostructure MOS capacitors

Novel low temperature techniques for growth of ultrathin oxides for Strained Si MOS Devices

Journal	Proceedings of the International Conference on Microelectronics, ICM
Open Access	No