A Study of High Temperature DC and AC Gate Stressing on the Performance and Reliability of Power SiC MOSFETs

2013 ◽  
Vol 740-742 ◽  
pp. 549-552 ◽  
Author(s):  
Ronald Green ◽  
A.J. Lelis ◽  
M. El ◽  
Daniel B. Habersat
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
State Of The Art ◽  
Temperature Measurements ◽  
Voltage Instability ◽  
Test Methodology ◽  
Full Effect ◽  
Oxide Trap ◽  
Bias Temperature Stress ◽  
Trap Activation

Although high-temperature measurements show a dramatic reduction in the bias-temperature stress-induced threshold-voltage instability of present state-of-the-art devices, a more thorough test methodology shows that several different conclusions may actually be drawn. The particular conclusion depends on the specific post-BTS measurement technique employed. Immediate room-temperature measurements suggest that significant oxide-trap activation may still be occurring. A significant, yet rapid, post-BTS recovery is observed as well. These results underline the importance of making both high-temperature and room-temperature measurements, as a function of stress and recovery time, to better ensure that the full effect of the BTS is observed. Initial AC BTS results suggest a similar level of device degradation as occurs from a DC BTS.

1700V, 5.5mOhm-cm2 4H-SiC DMOSFET with Stable 225°C Operation

2014 ◽  
Vol 778-780 ◽  
pp. 903-906 ◽  
Author(s):  
Kevin Matocha ◽  
Kiran Chatty ◽  
Sujit Banerjee ◽  
Larry B. Rowland
Keyword(s):  
High Temperature ◽  
Temperature Stress ◽  
High Temperatures ◽  
Threshold Voltage ◽  
Room Temperature ◽  
Gate Bias ◽  
Threshold Voltage Shift ◽  
Device Reliability ◽  
Bias Temperature Stress ◽  
High Temperature Operation

We report a 1700V, 5.5mΩ-cm24H-SiC DMOSFET capable of 225°C operation. The specific on-resistance of the DMOSFET designed for 1200V applications is 8.8mΩ-cm2at 225°C, an increase of only 60% compared to the room temperature value. The low specific on-resistance at high temperatures enables a smaller die size for high temperature operation. Under a negative gate bias temperature stress (BTS) at VGS=-15 V at 225°C for 20 minutes, the devices show a threshold voltage shift of ΔVTH=-0.25 V demonstrating one of the key device reliability requirements for high temperature operation.

Influence of High-Temperature Bias Stress on Room-Temperature VT Drift Measurements in SiC Power MOSFETs

2019 ◽  
Vol 963 ◽  
pp. 757-762
Author(s):  
Daniel B. Habersat ◽  
Aivars Lelis ◽  
Ronald Green
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
State Of The Art ◽  
Charge Trapping ◽  
High Temperature Stress ◽  
Test Method ◽  
Power Mosfets ◽  
Temperature Bias ◽  
Bias Stress

Our results reinforce the notion of the need for an improved high-temperature gate bias (HTGB) test method — one which discourages the use of slow (greater than ~1 ms) threshold-voltage (VT) measurements at elevated temperatures and includes biased cool-down if room temperature measurements are performed, to ensure that any ephemeral effects during the high-temperature stress are observed. The paper presents a series of results on both state-of-the-art commercially-available devices as well as older vintage devices that exhibit enhanced charge-trapping effects. Although modern devices appear to be robust, it is important to ensure that any new devices released commercially, especially by new vendors, are properly evaluated for VT stability.

Threshold-Voltage Instability in SiC MOSFETs Due to Near-Interfacial Oxide Traps

2016 ◽  
Vol 858 ◽  
pp. 585-590 ◽  
Author(s):  
Aivars J. Lelis ◽  
Ronald Green ◽  
Daniel B. Habersat
Keyword(s):  
Threshold Voltage ◽  
Charge Trapping ◽  
Test Methods ◽  
Device Failure ◽  
Voltage Instability ◽  
Oxide Trap ◽  
Oxide Traps ◽  
Trap Activation

There are two basic mechanisms that affect the threshold-voltage (VT) stability: oxide-trap activation and oxide-trap charging. Once additional oxide traps are activated, then they are free to participate in the charge-trapping processes that can, especially for older vintage devices, result in large VT shifts and potential device failure. More recent commercially-available devices show much smaller effects, and minimal trap activation. Given the dramatic improvements, it is now imperative that improved test methods be employed to properly separate out bad devices from good devices.

Elevated Temperature Fiber Push-Out Testing

1994 ◽  
Vol 365 ◽  
Author(s):  
J.I. Eldridge
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Experimental Procedure ◽  
Composite Systems ◽  
Test Methodology ◽  
Reinforced Composite ◽  
Critical Issues ◽  
Push Out ◽  
Potential Use

ABSTRACTThe potential use of fiber-reinforced composite materials for high temperature applications makes the development of interface test methodology at those high temperatures very desirable. A facility for performing high temperature fiber push-out tests will be described with emphasis on critical issues in experimental procedure. Examples from several composite systems illustrate the temperature dependence and environmental sensitivity of fiber debonding and sliding. Interpretation of the temperature dependence will be made primarily in terms of changes in residual stresses along with additional effects due to changes in matrix ductility and interfacial wear. Examples will show that high temperature fiber push-out testing can often distinguish between chemical and frictional fiber/matrix bonding in cases where room temperature only testing cannot.

Real Time Stress Measurements During Growth of Aluminum Nitride on SI(111) and SI(001)

1993 ◽  
Vol 308 ◽  
Author(s):  
W. J. Meng ◽  
J. A. Sell ◽  
G. L. Eesley ◽  
T. A. Perry
Keyword(s):  
High Temperature ◽  
Aluminum Nitride ◽  
Real Time ◽  
Room Temperature ◽  
Temperature Measurements ◽  
Silicon Substrates ◽  
Temperature Growth ◽  
Stress Measurements ◽  
Time Stress ◽  
Beam Reflection

ABSTRACTWe have performed real time measurements of intrinsic stresses during growth by reactive dc magnetron sputtering of aluminum nitride (AlN) thin films on silicon substrates in an UHV growth chamber. An experimental setup based on laser beam reflection is constructed such that substrate curvature as well as film thickness can be continuously monitored as growth proceeds. On Si(111) substrates, stress measurements were carried out during growth of both polycrystalline and epitaxial A1N films as a function of deposition pressure. This is the first such comparative study to our knowledge for the AlN/Si system. Our room temperature measurements on polycrystalline films corroborates previous post-growth measurements. Our high temperature measurements provide evidence of large intrinsic stresses and negligible stress relaxation during epitaxial growth of AlN on Si(111). We further compared stress behavior during both room temperature and high temperature growth of AlN films on Si(111) and Si(001) substrates. Our observations indicate while intrinsic stresses during room temperature growth can be compressive or tensile depending on plasma conditions, it is tensile during late stage growth at high temperatures.

scholarly journals Performance and Applications of Silicon Carbide Neutron Detectors in Harsh Nuclear Environments

2021 ◽  
Vol 253 ◽  
pp. 11003
Author(s):  
Frank H. Ruddy ◽  
Laurent Ottaviani ◽  
Abdallah Lyoussi ◽  
Christophe Destouches ◽  
Olivier Palais ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Room Temperature ◽  
Nuclear Reactor ◽  
State Of The Art ◽  
Radiation Detectors ◽  
Low Noise ◽  
Nuclear Radiation ◽  
High Radiation ◽  
Neutron Detectors

Silicon carbide (SiC) semiconductor is an ideal material for solid-state nuclear radiation detectors to be used in high-temperature, high-radiation environments. Such harsh environments are typically encountered in nuclear reactor measurement locations as well as high-level radioactive waste and/or “hot” dismantlingdecommissioning operations. In the present fleet of commercial nuclear reactors, temperatures in excess of 300 °C are often encountered, and temperatures up to 800 °C are anticipated in advanced reactor designs. The wide bandgap for SiC (3.27 eV) compared to more widely used semiconductors such as silicon (1.12 eV at room temperature) has allowed low-noise measurements to be carried out at temperatures up to 700 °C. The concentration of thermally induced charge carriers in SiC at 700 °C is about four orders of magnitude less than that of silicon at room temperature. Furthermore, SiC radiation detectors have been demonstrated to be much more resistant to the effects of radiation-induced damage than more conventional semiconductors such as silicon, germanium, or cadmium zinc telluride (CZT), and have been demonstrated to be operational after extremely high gamma-ray, neutron, and charged-particle doses. The purpose of the present review is to provide an updated state of the art for SiC neutron detectors and to explore their applications in harsh high-temperature, high-radiation nuclear reactor applications. Conclusions related to the current state-of-the-art of SiC neutron detectors will be presented, and specific ideal applications will be discussed.

ABOUT HEAT CAPACITY OF TITANIUM CARBIDE TiCx

2019 ◽  
pp. 56-66
Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Titanium Carbide ◽  
Temperature Dependence ◽  
Carbon Concentration ◽  
Room Temperature ◽  
Thermodynamic Characteristics ◽  
Liquid Nitrogen Temperature ◽  
Analysis Data ◽  
Thermal Excitation

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration  range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.

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