Threshold voltage instabilities in AlGaN/GaN MOS-HEMTs with ALD-grown Al2O3 gate dielectrics: Relation to distribution of oxide/semiconductor interface state density

2016 ◽  
Author(s):  
M. Tapajna ◽  
L. Valik ◽  
D. Gregusova ◽  
K. Frohlich ◽  
F. Gucmann ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Gate Dielectrics ◽  
Interface State ◽  
State Density ◽  
Interface State Density ◽  
Oxide Semiconductor ◽  
Semiconductor Interface

Processing and Characterization of MOS Capacitors Fabricated on 2°-Off Axis 4H-SiC Epilayers

2016 ◽  
Vol 858 ◽  
pp. 663-666
Author(s):  
Marilena Vivona ◽  
Patrick Fiorenza ◽  
Tomasz Sledziewski ◽  
Alexandra Gkanatsiou ◽  
Michael Krieger ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Interface State ◽  
State Density ◽  
Metal Oxide Semiconductor ◽  
Interface State Density ◽  
Device Fabrication ◽  
Oxide Semiconductor ◽  
Mos Capacitors ◽  
Oxide Breakdown

In this work, the electrical properties of SiO2/SiC interfaces onto a 2°-off axis 4H-SiC layer were studied and validated through the processing and characterization of metal-oxide-semiconductor (MOS) capacitors. The electrical analyses on the MOS capacitors gave an interface state density in the low 1×1012 eV-1cm-2 range, which results comparable to the standard 4°-off-axis 4H-SiC, currently used for device fabrication. From Fowler-Nordheim analysis and breakdown measurements, a barrier height of 2.9 eV and an oxide breakdown of 10.3 MV/cm were determined. The results demonstrate the maturity of the 2°-off axis material and pave the way for the fabrication of 4H-SiC MOSFET devices on this misorientation angle.

Analysis of Interface Trap Density and Channel Mobility in 4H-SiC NMOS Capacitors and Lateral MOSFETs

2017 ◽  
Vol 897 ◽  
pp. 115-118
Author(s):  
Martin Domeij ◽  
Jimmy Franchi ◽  
Krister Gumaelius ◽  
K. Lee ◽  
Fredrik Allerstam
Keyword(s):  
Threshold Voltage ◽  
Interface State ◽  
State Density ◽  
Interface State Density ◽  
Trap Density ◽  
Interface Trap Density ◽  
Interface Trap ◽  
Subthreshold Slope ◽  
Gate Oxides ◽  
Channel Mobility

Lateral implanted SiC MOSFETs and NMOS capacitors were fabricated and used to extract channel mobility and interface state density DIT for three different gate oxides. DIT values were extracted using the high(1 MHz)-low(1 kHz) method for NMOS capacitors and the subthreshold slope for MOSFETs. The subthreshold slope extraction gave 6-20 times higher DIT values compared to the high-low method, presumably because the high-low method cannot capture the fastest traps [1]. None of the methods resulted in clear proportionality between the inverse channel mobility and DIT. The subthreshold slope gave similar DIT values for samples with different surface p-doping concentrations indicating that the method is not sensitive to the threshold voltage.

Electrical Stability Impact of Gate Oxide in Channel Implanted SiC NMOS and PMOS Transistors

2017 ◽  
Vol 897 ◽  
pp. 513-516 ◽  
Author(s):  
Muhammad I. Idris ◽  
Ming Hung Weng ◽  
H.K. Chan ◽  
A.E. Murphy ◽  
Dave A. Smith ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Gate Oxide ◽  
Interface State ◽  
State Density ◽  
Interface State Density ◽  
Single Type ◽  
Electrical Stability ◽  
Wide Range ◽  
Flatband Voltage ◽  
The Impact

Operation of SiC MOSFETs beyond 300°C opens up opportunities for a wide range of CMOS based digital and analogue applications. However the majority of the literature focuses only on the optimization of a single type of MOS device (either PMOS or more commonly NMOS) and there is a lack of a comprehensive study describing the challenge of optimizing CMOS devices. This study reports on the impact of gate oxide performance in channel implanted SiC on the electrical stability for both NMOS and PMOS capacitors and transistors. Parameters including interface state density (Dit), flatband voltage (VFB), threshold voltage (VTH) and effective charge (NEFF) have been acquired from C-V characteristics to assess the effectiveness of the fabrication process in realising high quality gate dielectrics. The performance of SiC based CMOS transistors were analyzed by correlating the characteristics of the MOS interface properties, the MOSFET 1/f noise performance and transistor on-state stability at 300°C. The observed instability of PMOS devices is more significant than in equivalent NMOS devices. The results from MOS capacitors comprising interface state density (Dit), flatband voltage (VFB), threshold voltage (VTH) for both N and P MOS are in agreement with the expected characteristics of the respective transistors.

Fabrication of High Quality MOS Devices for Application in Hazardous Environments Based on RTP Gate Dielectrics with In Situ RTCVD of Polysilicon Gates

1993 ◽  
Vol 300 ◽  
Author(s):  
B. Fröschle ◽  
H.P. Bruemmer ◽  
W. Lang ◽  
K. Neumeier ◽  
P. Ramm
Keyword(s):  
Threshold Voltage ◽  
Gate Dielectrics ◽  
Chemical Vapor ◽  
Process Variations ◽  
Interface State ◽  
State Density ◽  
Breakdown Field ◽  
Polysilicon Gate ◽  
Radiation Induced

ABSTRACTProcess modules for MOS gate fabrication were developed which can be completed subsequently in one RTP reactor: atmospheric process sequences for gate oxides and oxynitrides as well as low pressure chemical vapor deposition of polysilicon (RTCVD). Prior to the Rapid Thermal Oxidation (RTO), the wafers were treated with a Rapid Thermal Cleaning process (RTC) in H2/Ar ambient. After the desoxidation step the RTO was done in O2/H2/Ar followed by an anneal (RTA) for the gate oxide or a nitridation in NH3 (RTN) and reoxidation for the oxynitrides, respectively. The polysilicon gate electrode was fabricated either by RTCVD in situ or in a conventional furnace reactor. The two-step RTCVD process resulted in a very good thickness uniformity for the polysilicon layers of 3% (3mm from the edge). The influence of the process variations on breakdown field, fixed oxide charge, interface state density, flatband voltage, and threshold voltage of the different types of gate dielectrics was investigated. The charges and voltages were determined by LF-HF CV measurements. In order to characterize the radiation tolerance of electronic devices, radiation induced flatband and threshold voltage shifts as well as the build up of interface charges were determined. The irradiation was performed at a Co - 60 gamma source. Breakdown fields in the range of 19 MV/cm, interface state densities of less than 109 eV−1cm−2, and radiation induced threshold voltage shifts below 0.1 V after 1.5 Mrad(Si) were obtained.

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