Active solid-state devices (e.g. – transistors – solid-state diode – Specified wide band gap semiconductor material other than... – Diamond or silicon carbide
Patent
1996-08-08
1998-05-19
Munson, Gene M.
Active solid-state devices (e.g., transistors, solid-state diode
Specified wide band gap semiconductor material other than...
Diamond or silicon carbide
257136, 257192, 257264, H01L 29161, H01L 29808
Patent
active
057539383
ABSTRACT:
A semiconductor switching device includes a plurality of adjacent heterojunction-gate static-induction transistor (SIT) unit cells connected in parallel in a monocrystalline silicon carbide substrate having first and second opposing faces, a relatively highly doped silicon carbide drain region adjacent the first face and a relatively highly doped silicon carbide source region adjacent the second face. A relatively lightly doped drift region is also provided in the substrate and extends between the drain region and source region. A plurality of trenches are also provided in the substrate so that sidewalls of the trenches extend adjacent the drift region. Each trench preferably contains a relatively highly doped second conductivity type nonmonocrystalline silicon gate region comprised of a material selected from the group consisting of polycrystalline silicon or amorphous silicon. These gate regions form P-N heterojunctions with the drift region at the sidewalls and bottoms of the trenches. An electrically insulating layer, such as a thermally grown silicon dioxide layer, is also provided on the nonmonocrystalline silicon gate regions in order to electrically insulate the gate regions from metallization on the second face. The use of nonmonocrystalline materials for the gate regions is preferred because the nonmonocrystalline lattice structure of the gate regions provides numerous grain boundaries and other lattice defects which act as scattering sites for electrons. By providing scattering sites, the probability that accelerated electrons will reach the threshold energy to induce avalanche breakdown in the gate regions is reduced and an increase in forward blocking voltage capability is achieved. Hole injection from the P+ polycrystalline silicon gate region into the N-type drift can also be suppressed to significantly improve the switching speed by reducing the amount of stored charge in the drift region.
REFERENCES:
patent: 4375124 (1983-03-01), Cogan
patent: 4484207 (1984-11-01), Nishizawa et al.
patent: 4587712 (1986-05-01), Baliga
patent: 4757028 (1988-07-01), Kondoh et al.
patent: 5323040 (1994-06-01), Baliga
patent: 5396085 (1995-03-01), Baliga
patent: 5406096 (1995-04-01), Malhi
patent: 5436174 (1995-07-01), Baliga et al.
patent: 5536953 (1996-07-01), Dreifus et al.
patent: 5612547 (1997-03-01), Clarke et al.
R.R. Siergiej et al., High Power 4H-SiC Static Induction Transistors, IEDM, pp. 353-356 (1995).
B. Jayant Baliga, Power Rectifiers, Chapters 4, Power Semiconductor Devices, PWS Publishing, pp. 128-143 (1996).
N.A. Papanicolaou et al., Pt and PTSi.sub.x Schottky Contacts On N-type .beta.-SiC, J. Appl. Phys., vol. 65, No. 9, pp. 3526-3530, May (1989).
J.N. Su et al., Fabrication of High Voltage SiC Schottky Barrier Diodes by Ni Metallization, Inst. Phys. Conf. Ser. No. 142, Chapter 4, Silicon Carbide and Related Materials Conference, Kyoto, Japan, pp. 697-700 (1995).
I.A. Blech et al., Optimization of Al Step Coverage Through Computer Simulation and Scanning Electron Microscopy, J. Vac. Sci. Technol., vol. 15, No. 1, pp. 13-19 (1978).
M. Kothandaraman et al., Reactive Ion Etching of Trenches in 6H-SiC, Journal of Electronic Materials, vol. 25, No. 5, pp. 857-878 (1996).
T.I. Kamins, Oxidation of Phosphorus-Doped Low Pressure and Atmospheric Pressure CVD Polycrystalline-Silicon Films, Journ. Electrochem. Soc., Solid-State Science and Technology, pp. 838-844 May (1979).
A.K. Agarwal et al., A Critical Look at the Performance Advantages and Limitations of 4H-SiC Power UMOSFET Structures, Proceedings to the 8th International Symposium on Power Semiconductor Devices and ICs, pp. 119-122 (1996).
Hideo Sunami, Thermal Oxidation of Phosphorus-Doped Polycrystalline Silicon in Wet Oxygen, Journ. Electrochem. Soc., Solid-State Science and Technology, vol. 125, No. 6, pp. 892-897.
J.B. Petit et al., Thermal Oxidation of Single-Crystal Silicon Carbide: Kinetic, Electrical, and Chemical Studies, Amorphous and Crystalline Silicon Carbide IV, Springer Proceedings in Physics, vol. 71, pp. 190-196 (1992).
Baliga Bantval Jyant
Muraleedharan Shenoy Praveen
Thapar Naresh I.
Munson Gene M.
North Carolina State University
LandOfFree
Static-induction transistors having heterojunction gates and met does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Static-induction transistors having heterojunction gates and met, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Static-induction transistors having heterojunction gates and met will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1855363