| 1. |
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| 2. |
- Jeppson, Kjell, 1947, et al.
(författare)
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The effects of impurity redistribution of the subthreshold leakage current in CMOS n-channel transistors
- 1976
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Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101. ; 19:1, s. 83-85
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Tidskriftsartikel (refereegranskat)abstract
- A study of subthreshold leakage current in n-channel transistors on low threshold voltage CMOS circuits has been made. Redistribution of impurities at the silicon surface during thermal oxidation is shown to be the main cause of excess subthreshold leakage current. Processing techniques to minimize this leakage have been developed.
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| 3. |
- Jeppson, Kjell, 1947, et al.
(författare)
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Unintentional writing of a FAMOS memory device during reading
- 1976
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Ingår i: Solid-State Electronics. - 0038-1101. ; 19:6, s. 455-457
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Tidskriftsartikel (refereegranskat)abstract
- A FAMOS cell may be unintentionally written during repeated reading. The temperature dependence of this failure process was studied and it is shown that the worst case for unintentional charging of a FAMOS device occurs at low temperatures. This is qualitatively explained by a simple model including the temperature dependence of preavalanche carrier multiplication and hot electron injection.
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| 4. |
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| 5. |
- Lee, S. K., et al.
(författare)
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Reduction of the Schottky barrier height on silicon carbide using Au nano-particles
- 2002
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 46:9, s. 1433-1440
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Tidskriftsartikel (refereegranskat)abstract
- By the incorporation of size-selected Au nano-particles in Ti Schottky contacts on silicon carbide, we could observe considerably lower the barrier height of the contacts. This result could be obtained for both n- and p-type Schottky contacts using current-voltage and capacitance voltage measurements. For n-type Schottky contacts, we observed reductions of 0.19-0.25 eV on 4H-SiC and 0.15-0.17 eV on 6H-SiC as compared with particle-free Ti Schottky contacts. For p-type SiC, the reduction was a little lower with 0.02-0.05 eV on 4H- and 0.10-0.13 eV on 6H-SiC. The reduction of the Schottky barrier height is explained using a model with enhanced electric field at the interface due to the small size of the circular patch and the large difference of the barrier height between Ti and Au.
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| 6. |
- Linder, M., et al.
(författare)
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On DC modeling of the base resistance in bipolar transistors
- 2000
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 44:8, s. 1411-1418
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Tidskriftsartikel (refereegranskat)abstract
- The total base resistance R-BTot constitutes a crucial parameter in modeling bipolar transistors. The significant physical effects determining R-BTot are current crowding and conductivity modulation in the base, both causing reduction of R-BTot With increasing base current I-B. In this paper, it is shown that the reduction of R-BTot(I-B) With increasing I-B is directly related to the physical effect dominating in the base. A new model for R-BTot(I-B) is presented where a parameter alpha is introduced to account for the contributions of current crowding and conductivity modulation in the base. Theoretically, alpha is equal to 0.5 when conductivity modulation is dominant and close to 1.0 when current crowding is the most significant effect. This was verified by measurements and simulations using a distributed transistor model which accounts for the lateral distribution of the base current and the stored base charge. The model proposed for R-BTot(I-B) is very suitable for compact transistor modeling since it is given in a closed form expression handling both current crowding and conductivity modulation in the base. An accurate extraction procedure of the model parameters is also presented.
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| 7. |
- Danielson, E., et al.
(författare)
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Investigation of thermal properties in fabricated 4H-SiC high power bipolar transistors
- 2003
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 47:4, s. 639-644
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Tidskriftsartikel (refereegranskat)abstract
- Silicon carbide bipolar junction transistors have been fabricated and investigated. The transistors had a maximum current gain of approximately 10 times, and a breakdown voltage of 450 V. When operated at high power densities the device showed a clear self-heating effect, decreasing the current gain. The junction temperature was extracted during self-heating to approximately 150 degreesC, using the assumption that the current gain only depends on temperature. Thermal images of a device under operation were also recorded using an infrared camera, showing a significant temperature increase in the vicinity of the device. The device was also tested in a switched setup, showing fast turn on and turn off at 1 MHz and 300 V supply voltage. Device simulations have been used to analyze the measured data. The thermal conductivity is fitted against the self-heating, and the lifetime in the base is fitted against the measurement of the current gain.
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| 8. |
- Bertilsson, Kent, et al.
(författare)
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The Effect of Different Transport Models in Simulation of High Frequency 4H-SiC and 6H-SiC Vertical MESFETs
- 2001
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 45:5, s. 645-653
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Tidskriftsartikel (refereegranskat)abstract
- A full band Monte Carlo (MC) study of the high frequency performance of a 4H-SiC Short channel vertical MESFET is presented. The MC model used is based on data from a full potential band structure calculation using the local density approximation to the density functional theory. The MC results have been compared with simulations using state of the art drift-diffusion and hydrodynamic transport models. Transport parameters such as mobility, saturation velocity and energy relaxation time are extracted from MC simulations
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| 9. |
- Danielsson, E., et al.
(författare)
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The influence of band offsets on the IV characteristics for GaN/SiC heterojunctions
- 2002
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 46:6, s. 827-835
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Tidskriftsartikel (refereegranskat)abstract
- GaN/SiC heterojunctions can improve the performance considerably for bipolar transistors based on SiC technology. In order to fabricate such devices with a high current gain, the origin of the low turn-on voltage for the heterojunction has to be investigated, which is believed to decrease the minority carrier injection considerably. In this work heterojunction diodes are compared and characterized. For the investigated diodes, the GaN layers have been grown by molecular beam epitaxy (MBE), metal organic chemical vapor deposition, and hydride vapor phase epitaxy. A diode structure fabricated with MBE is presented here, whereas others are collected from previous publications. The layers were grown either with a low temperature buffer, AIN buffer, or without buffer layer. The extracted band offsets are compared and included in a model for a recombination process assisted by tunneling, which is proposed as explanation for the low turn-on voltage. This model was implemented in a device simulator and compared to the measured structures, with good agreement for the diodes with a GaN layer grown without buffer layer. In addition the band offset has been calculated from Schottky barrier measurements, resulting in a type II band alignment with a conduction band offset in the range 0.6-0.9 eV. This range agrees well with the values extracted from capacitance-voltage measurements.
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| 10. |
- Domeij, Martin, et al.
(författare)
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Dynamic avalanche in Si power diodes and impact ionization at the nn(+) junction
- 2000
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 44:3, s. 477-485
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Tidskriftsartikel (refereegranskat)abstract
- The reverse recovery failure limit was measured with an optical technique for power diodes which sustain high levels of dynamic avalanche. Measurements and simulations indicate that these diodes withstand dynamic avalanche at the pn-junction and eventually fail as a result of a strongly inhomogeneous current distribution caused by the onset of impact ionisation at the diode nn(+) junction - a mechanism similar to the reverse bias second breakdown of bipolar transistors.
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