sogang university sogang university. semiconductor device lab. breakdown voltage(1) 2013.01.02 sd...
TRANSCRIPT
![Page 1: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/1.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
Breakdown Voltage(1)
2013.01.02SD Lab. SOGANG Univ.
Doohyung Cho
![Page 2: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/2.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
Contents
3.1 Avalanche Breakdown 3.1.1 Power Law Approximations for the Impact Ionization Coeffi-cients 3.1.2 Multiplication Coefficient3.2 Abrupt One-Dimensional Diode3.3 Ideal Specific On-Resistance3.4 Abrupt Punch-Though Diode3.5 Linearly Graded Junction Diode3.6 Edge Terminations 3.6.1 Planar Junction Termination 3.6.2 Planar Junction with Floating Field Ring 3.6.3 Planar Junction with Multiple Floating Field Rings
![Page 3: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/3.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.1 Avalanche Breakdown
• Mobile carriers are accelerated in the presence of a high electric field until they gain sufficient energy to create hole–electron pairs upon collision with the lattice atoms.
• An impact ionization coefficient was defined as the number of elec-tron–hole pairs created by a mobile carrier traversing 1 cm through the depletion region along the direction of the electric field.
![Page 4: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/4.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.1.1 Power Law Approximations for the Impact Ion-ization Coefficients
• Fulop’s approxima-tion
• Baliga’s approxima-tion
• dashed line together with the impact ionization coefficient for electrons in silicon as governed by the Chynoweth’s law (shown by the solid line)
![Page 5: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/5.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.1.2 Multiplication Coefficient
• The avalanche breakdown condition is defined by the impact ionization rate becoming infinite
• Total number of electron–holes pairs created as a result of the genera-tion of a single electron–hole pair at a distance x from the junction
![Page 6: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/6.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.2 Abrupt One-Dimensional Diode
![Page 7: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/7.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.2 Abrupt One-Dimensional Diode
![Page 8: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/8.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.3 Ideal Specific On-Resistance
![Page 9: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/9.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.4 Abrupt Punch-Through Diode
• Resistance of the drift region is greatly reduced during on-state cur-rent flow by the injection of a large concentration of minority carriers.
![Page 10: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/10.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.5 Linearly Graded Junction Diode
![Page 11: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/11.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.6 Edge Terminations
• If the junction depth is 1 μm and the depletion region has a thickness of 30 μm, the maximum electric field at the cylindrical junction will be 15 times larger than that for the parallel-plane case
• Power devices with high breakdown voltages require large junction depths to reduce the degradation of the breakdown voltage due to junction curva-ture
![Page 12: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/12.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.6 Edge Terminations
![Page 13: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/13.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.6 Edge Terminations
• Electric field is enhanced even fur-ther than for the cylindrical junction, because the field lines approach a point in three dimensions for the spherical junction
• If the junction depth is 1 μm and the depletion region has a thickness of 30 μm, the maximum electric field at the spherical junction will be 20 times larger than that at the cylin-drical junction
![Page 14: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/14.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.6.2 Planar Junction with Floating Field Ring
• Floating field ring must be located at an optimal position to maximize the breakdown voltage
![Page 15: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/15.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.6.2 Planar Junction with Floating Field Ring
• The optimum spacing is in the range of 0.15–0.35 times the deple-tion layer width for the parallel-plane junction at breakdown
![Page 16: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/16.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.6.2 Planar Junction with Floating Field Ring
• The presence of a negative charge in the oxide compensates the positive charge at the ionized donors, producing an extension of the depletion layer along the sur-face. The presence of a positive charge has the opposite effect on the depletion layer at the surface.
• When Fixed Oxide Charge=1011cm-2
(Breakdown voltage is degraded 50V)
![Page 17: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/17.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.6.2 Planar Junction with Floating Field Ring
• It is necessary to make the width of the floating field ring at least equal to the depletion width (WPP) of the parallel-plane junction at breakdown
![Page 18: SOGANG UNIVERSITY SOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB. Breakdown Voltage(1) 2013.01.02 SD Lab. SOGANG Univ. Doohyung Cho](https://reader035.vdocuments.us/reader035/viewer/2022062407/56649d225503460f949f83c3/html5/thumbnails/18.jpg)
SOGANG UNIVERSITYSOGANG UNIVERSITY. SEMICONDUCTOR DEVICE LAB.
3.6.3 Planar Junction with Multiple Floating Field Rings
• The optimization of the spacing between the rings requires a precise knowledge of the charge in the field oxide
• There is a diminishing benefit in terms of increasing the break-down voltage from the addition of floating rings, while more space is occupied by the edge termination resulting in a larger die size and cost.