Abstract
We investigated the effects of in situ silicon carbon nitride (SiCN) cap layer of AlGaN/GaN high-electron mobility transistors (HEMTs) on DC, capacitance-voltage (C-V) and low-frequency noise (LFN). The proposed device with SiCN cap layer exhibited enhanced drain current, reduced gate leakage current, low interface trap density (Dit), and high on/off ratio thanks to the passivation effect, compared to the device without SiCN cap layer. Both devices clearly showed 1/f noise behavior with carrier number fluctuations (CNF), regardless of the existence of SiCN cap layer. The proposed device presented the relative low trap density (Nit) and reduced access noise due to the effective surface passivation in source-drain access region compared to the device without SiCN cap layer. From the improved DC, C-V and noise results of the proposed device, the in situ SiCN cap layer plays an important role in the passivation layer and gate oxide layer in AlGaN/GaN HEMT.
Highlights
Owing to superior GaN material properties such as wide band gap (3.4 eV), high electron saturation velocity (2.5 × 107 cm/s), and large breakdown electric field (3.3 MV/cm), AlGaN/GaN high-electron mobility transistors (HEMTs) have many advantages for highpower and high-frequency device applications [1]
The drain current for the fabricated AlGaN/GaN HEMTs with silicon carbon nitride (SiCN) cap layer exhibits the negative shift of threshold voltage (Vth ) of approximately
This is reflected in the fact that the SiCN cap layer effectively passivates the AlGaN surface, which results in reducing the gate leakage current
Summary
Owing to superior GaN material properties such as wide band gap (3.4 eV), high electron saturation velocity (2.5 × 107 cm/s), and large breakdown electric field (3.3 MV/cm), AlGaN/GaN high-electron mobility transistors (HEMTs) have many advantages for highpower and high-frequency device applications [1]. Lee et al [7] reported improved device performance by utilizing an in situ silicon carbon nitride (SiCN) cap layer, due to the enhanced surface passivation effect. There is no report on the effect of the gate dielectric on noise performance of AlGaN/GaN HEMTs with in situ SiCN cap layer. We fabricate, characterize, and compare the AlGaN/GaN HEMTs with and without SiCN cap layer by considering high resolution X-ray diffraction (HRXRD), Hall effects, transmission electron microscopy (TEM), DC, capacitance-voltage (C-V), and low-frequency noise (LFN). These characteristics provide information on the effects of the. SiCN cap layer on the device and the LFN performance of the fabricated devices
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
