Effect of sputtering time on physical and electrical properties of ZrO_x thin film on Si

Abstract

Purpose

The purpose of this paper is to report the effect of sputtering time on the electrical and physical properties of ZrO_x. ZrO_x (measured thickness is ranging from 20.5 to 51.3 nm) thin films as gate oxide materials are formed by metal deposition at different sputtering time and thermal oxidation techniques.

Design/methodology/approach

Zirconium is deposited on silicon substrate at three different sputtering time; 30‐, 60‐ and 120‐s continued with an oxidation process conducted at 500°C for 15 min to form ZrO_x thin films. High‐resolution X‐ray diffraction (HR‐XRD), Fourier transform infrared (FTIR) spectroscopy and electrical characterizations were used to examine the properties of the thin film.

Findings

A broad ZrO_x peak lies in between 26° and 31° from HR‐XRD is presumed as the effect of small thickness of ZrO_x and or the ZrO_x is still partially crystalline. FTIR spectroscopy results suggested that besides ZrO_x, SiO_x interfacial layer (IL) has also formed in all of the investigated samples. As the sputtering time increases, hysteresis between the forward and reverse bias of capacitance‐voltage curve has reduced. The lowest leakage current density and the highest oxide breakdown voltage have been demonstrated by 60‐s sputtered sample. These may be attributed to a lower effective oxide charge and interface trap density. The extracted dielectric constant (κ) of these oxides is ranging from 9.4 to 18, in which the κ value increases with the increase in sputtering time.

Originality/value

ZrO_x thin film which was fabricated by sputtering method at different sputtering time and thermal oxidation techniques showed distinctive electrical results. SiO_x IL formed in the samples.

Citation

Tedi, K., Cheong, K.Y. and Lockman, Z. (2011), "Effect of sputtering time on physical and electrical properties of ZrO_x thin film on Si", Microelectronics International, Vol. 28 No. 3, pp. 7-11. https://doi.org/10.1108/13565361111162567