Active solid-state devices (e.g. – transistors – solid-state diode – Field effect device – Having insulated electrode
Patent
1995-12-22
1997-06-10
Jackson, Jerome
Active solid-state devices (e.g., transistors, solid-state diode
Field effect device
Having insulated electrode
257331, 257333, 257342, H01L 2994
Patent
active
056378980
ABSTRACT:
A power transistor having high breakdown voltage and low on-state resistance includes a vertical field effect transistor in a semiconductor substrate having a plurality of source, channel, drift and drain regions therein. A trench having a bottom in the drift region and opposing sidewalls which extend adjacent the drift, channel and source regions is also provided in the substrate, at a face thereof. The trench preferably includes an insulated gate electrode therein for modulating the conductivity of the channel and drift regions in response to the application of a turn-on gate bias. The insulated gate electrode includes an electrically conductive gate in the trench and an insulating region which lines a sidewall of the trench adjacent the channel and drift regions. The insulating region has a nonuniform cross-sectional area between the trench sidewall and the gate which enhances the forward voltage blocking capability of the transistor by inhibiting the occurrence of high electric field crowding at the bottom of the trench. The thickness of the insulating region is preferably greater than 1500 .ANG. along the portion of the sidewall which extends adjacent the drift region and less than 750 .ANG. along the portion of the sidewall which extends adjacent the channel region. To provide low on-state resistance, the drift region is also nonuniformly doped to have a linearly graded doping profile which decreases from greater than about 1.times.10.sup.17 cm.sup.-3 to less than about 5.times.10.sup.-16 cm.sup.-3 in a direction from the drain region to the channel region.
REFERENCES:
patent: 3412297 (1968-11-01), Amlinger
patent: 4288801 (1981-09-01), Ronen
patent: 4893160 (1990-01-01), Blanchard
patent: 4903189 (1990-02-01), Ngo et al.
patent: 4914058 (1990-04-01), Blanchard
patent: 5072266 (1991-12-01), Bulucea et al.
patent: 5202750 (1993-04-01), Gough
patent: 5233215 (1993-08-01), Baliga
patent: 5283201 (1994-02-01), Tsang et al.
patent: 5298781 (1994-03-01), Cogan et al.
patent: 5323040 (1994-06-01), Baliga
patent: 5473176 (1995-12-01), Kakumoto
patent: 5558313 (1996-09-01), Hshieh et al.
Y. Babe, et al., A Study on a High Blocking Voltage UMOS-FET with a Double Gate Structure, Proceedings of 1992 International Symposium on Power Semiconductor Devices & ICs, Tokyo, pp. 300-302. No Month.
M. Bhatnagar and B. J. Baliga, Analysis of Silicon Carbide Power Device Performance, IEEE, 1991, pp. 176-180. No Month.
T. Syau, et al., Extended Trench-Gate Power UMOSFET Structure with Ultralow Specific On-Resistance, Electronics Letters, vol. 28, No. 9, Apr., 1992, pp. 865-867.
Hiroo Fuma, et al., High Temperature Operated Enhancement-Type .beta.-SiC MOSFET, Japanese Journal of Applied Physics, vol. 27, No. 11, Nov., 1988, pp. L2143-L2145.
B. Jayant Baliga, Power MOSFET, Chapter 7, Power Semiconductor Devices, 1996, pp. 335-425. No Month.
H.-R. Chang, Numerical And Experimental Comparison Of 60V Vertical Double-Diffused MOSFETS And MOSFETS With A Trench-Gate Structure, Solid-State Electronics, vol. 32, no. 3, 1989, pp. 247-251.
S. Merchant, et al., Realization Of High Breakdown Voltage (>700V) In Thin SOI Devices, IEEE, 1991, pp. 31-35. No Month.
T. Syau, et al., Comparison Of Ultralow Specific On-Resistance UMOSFET Structures: The ACCUFET, EXTFET, INVFET, and Conventional UMOSFET's, IEEE Transactions on Electron Devices, vol. 41, No. 5, May 1994, pp. 800-808.
M. Bhatnagar, et al., SiC Power UMOSFET: Design, Analysis And Technological Feasibility, Inst. Phys. Conf. Ser. No. 137: Chapter 7, 1994, pp. 703-706. No Month.
B. Jayant Baliga, New Materials Beyond Silicon For Power Devices, Power Semiconductor Devices and Circuits, 1992, pp. 377-389. No Month.
Bhatnagar, et al., Comparison of 6H-SiC, 3C-SiC, and Si For Power Devices, IEEE Transactions On Electron Devices, vol. 40, No. 3, Mar. 1993, pp. 645-655.
Alok, et al., Thermal Oxidation of 6H-Silicon Carbide at Enhanced Growth Rates, IEEE Electron Device Letters, vol. 15, No. 10, Oct. 1994, pp. 424-426.
Shenoy et al., Planar, Ion Implanted, High Voltage 6H-SiC P-N Junction Diodes, IEEE Electron Device Letters, vol. 16, No. 10, Oct. 1995, pp. 454-456.
A. Moki, et al., Low Resistivity As-Deposited Ohmic Contacts to 3C-SiC, Journal of Electronic Materials, vol. 24, No. 4, 1995, pp. 315-318. No Month.
Alok, et al., A Novel Method For Etching Trenches In Silicon Carbide, Journal of Electronic Materials, vol. 24, No. 4, 1995, pp. 311-314. No Month.
Alok, et al., Electrical properties of thermal oxide grown using dry oxidation on p-type 6H-silicon carbide, Appl. Phys. Lett., vol. 65, No. 17, Oct. 24, 1994, pp. 2177-2178.
Alok, et al., A Simple Edge Termination for Silicon Carbide Devicces with Nearly Ideal Breakdown Voltgage, IEEE Electron Device Letters, vol. 15, No. 10, Oct. 1994, pp. 394-395.
Alok, et al., Electrical properties of thermal oxide grown on n-type 6H-silicon carbide, Appl. Phys. Lett., vol. 64, No. 21, May 23, 1994, pp. 2845-2846.
Alok, et al., Low Contact Resistivity Ohmic Contacts to 6H-Silicon Carbide, IEDM 93, pp. 691-695. No Date.
M. Bhatnagar, et al., Comparison Of Ti And Pt Silicon Carbide Schottky Rectifiers, IEDM 92, pp. 789-792. No Date.
M. Bhatnagar, et al., Silicon-Carbide High-Voltage (400 V) Schottky Barrier Diodes, IEEE Electron Device Letters, vol. 13, No. 10, Oct. 1992, pp. 501-503.
Guay John
Jackson Jerome
North Carolina State University
LandOfFree
Vertical field effect transistors having improved breakdown volt does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Vertical field effect transistors having improved breakdown volt, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vertical field effect transistors having improved breakdown volt will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-767039