Analysis of C-Face 4H-SiC MOS Capacitors with ZrO₂ Gate Dielectric

Abstract

ZrO2 films were deposited on C-face 4H-SiC substrates by using an RF sputter at a temperature of 200°C. Then, ZrO2 films were treated with RTA (rapid thermal annealing) process in Argon (Ar) ambient at 600°C, 700°C and 800°C for 4 minutes, respectively. The samples with RTA process show the lower leakage currents. As the measure temperature increases from room temperature (RT) to 150°C, the dielectric breakdown voltage reduces from 3 V to 1 V. The difference between quasi C-V characteristics and high frequency C-V characteristics at 1 MHz becomes larger with increasing RTA temperature. The C-V curves also shift to the left side as the measure temperature increases from RT to 150°C. It also shows the ledge on the C-V curves of samples with RTA at elevated measure temperature.

Structural and Insulating Behaviour of High-Permittivity Binary Oxide Thin Films for Silicon Carbide and Gallium Nitride Electronic Devices

“…Moreover, other high-κ binary oxides with larger band gaps and more favourable band alignment with SiC, such as Al 2 O 3 [101], La 2 O 3 [59,103], and ZrO 2 [104,105], have been investigated.…”

A new 4H-SiC hydrogen sensor with oxide ramp termination

“…Therefore, in order to increase the sensitivity, alternative insulator layers replacing SiO 2 (i.e. HfO 2 , HfO 2 /SiO 2 [15], ZrO 2 [16], Al 2 O 3 [17], AlN [18], and Ta 2 O 5 [7,19]) as well as post-oxidation treatments have been investigated. Another crucial issue for MOS capacitors, especially those operating under extreme conditions, is the reliability of gate dielectrics [20].…”

Electronic Properties of Stacked ZrO2 Films Fabricated by Atomic Layer Deposition on 4H-SiC

“…Although SiC can be thermally oxidized resulting in formation of SiO 2 layer, the application of relatively small dielectric constant material (κ SiO2 = 3.9) leads to a premature breakdown of the MOSFET gate. Since the breakdown mechanism of the device is related to the Gauss law the high-κ dielectrics were proposed as an alternative gate material for SiC power devices [2][3][4]. Hafnium oxide (HfO 2 ) [2], aluminum oxide (Al 2 O 3 ) [3] or zirconium oxide (ZrO 2 ) [4] single dielectric layers have been investigated in recent years for application as gate dielectric.…”

“…Since the breakdown mechanism of the device is related to the Gauss law the high-κ dielectrics were proposed as an alternative gate material for SiC power devices [2][3][4]. Hafnium oxide (HfO 2 ) [2], aluminum oxide (Al 2 O 3 ) [3] or zirconium oxide (ZrO 2 ) [4] single dielectric layers have been investigated in recent years for application as gate dielectric. However, two main drawbacks limit a successful implementation: HfO 2 and ZrO 2 , materials with dielectric constant higher than that for SiC (κ SiC = 9.66), have been reported to form relatively small conduction band offset for electrons resulting in an extensive leakage current (≈ 1.07 eV for HfO 2 and ≈ 0.94 eV for ZrO 2 , respectively [5]).…”