Suppression of Leakage Current of Deposited SiO2 with Bandgap Increasing by High Temperature Annealing

Ion implantation and a subsequent annealing at high temperature are required for fabricating a high voltage Schottky Barrier Diode (SBD) with a field limiting ring (FLR) or a junction termination extension (JTE), but high temperature annealing degrades surface condition of a SiC substrate and induces a degradation of electronic characteristics of a fabricated SBD. To avoid a degradation of SBD electronic characteristics after high temperature annealing, the method of removing a degraded layer from a SiC surface by sacrificial oxidation after high temperature annealing is studied. In this study, we studied the relationship between the improvement of SBD electronic characteristics and the thickness of sacrificial oxide grown after high temperature annealing. 9~12 SBD without edge termination were fabricated on a SiC substrate of 4mm×4mm. The ratio of good chips to all chips (9~12 SBD) increases with increasing total thickness of sacrificial oxide grown after high temperature annealing at 1800oC for 30 s, where an SBD with a leakage current less than 1μA/cm2 at reverse voltage of –100V was defined as a good chip. We applied this process growing sacrificial oxide of 150nm after high temperature annealing to fabricate the SBD with an FLR structure designed with 600V blocking voltage on a Si-face SiC substrate. The SBD with an FLR structure through this process of 150 nm sacrificial oxide is low leakage current of less than 1μA/cm2 at reverse voltage of –100V and achieves 600V blocking voltage, however, the SBD with an FLR structure without the process of sacrificial oxide after high temperature annealing is high leakage current at reverse voltage of –100V. It is shown that this process growing sacrificial oxide after high temperature annealing is useful to fabricate an SBD with an FLR structure.

Download Full-text

Modification of Surface Layer during High Temperature Annealing and its Effects on the SiC Diode Characteristics

Materials Science Forum ◽

10.4028/www.scientific.net/msf.556-557.595 ◽

2007 ◽

Vol 556-557 ◽

pp. 595-598 ◽

Cited By ~ 1

Author(s):

Wook Bahng ◽

Hui Jong Cheong ◽

In Ho Kang ◽

Seong Jin Kim ◽

Sang Cheol Kim ◽

...

Keyword(s):

Surface Layer ◽

High Temperature ◽

Leakage Current ◽

Breakdown Voltage ◽

Schottky Diodes ◽

High Temperature Annealing ◽

Conductive Layer ◽

Pin Diodes ◽

Ohmic Behavior ◽

Surface Modified

We have investigated the influence of surface modification on the electrical properties of SiC diodes. Schottky diodes (SBDs) as well as PiN diodes were fabricated on n-type SiC substrate with an epilayer, and electrically characterized before and after high temperature annealing, and after removing the surface modified layer, respectively. The devices annealed without graphite cap layer showed ohmic behavior. The surface layer was modified to a conductive layer possibly due to the preferred sublimation of Si species. In order to confirm the existence of modified surface conductive layer, diode was fabricated on the same substrate and electrically characterized after removing 30nm-thick damaged layer by ICP-RIE. The leakage current reduced dramatically, as much as 7 orders of magnitude. The PiN diodes fabricated on the damaged surface layer showed the reverse leakage current and the breakdown voltage of 50mA and 1250V, respectively. While those of the diode fabricated after removing the damaged surface layer were 200nA at the breakdown voltage of 2100V, respectively.

Download Full-text

Leakage Currents through Thin Silicon Oxide Grown on Atomically Flat Silicon Surfaces

MRS Proceedings ◽

10.1557/proc-849-kk7.11 ◽

2004 ◽

Vol 849 ◽

Author(s):

Valerian Ignatescu ◽

Jack M. Blakely

Keyword(s):

High Temperature ◽

Leakage Current ◽

Silicon Oxide ◽

Silicon Surfaces ◽

High Temperature Annealing ◽

Chemical Cleaning ◽

Flat Surfaces ◽

Stepped Surfaces ◽

Thin Silicon ◽

Atomically Flat

ABSTRACTAtomically flat surfaces can be obtained by high-temperature annealing in UHV of specially patterned silicon samples. Thin silicon oxide layers were grown by dry oxidation on three types of surfaces: (a) atomically flat surfaces, (b) normal (stepped) surfaces cleaned in UHV by the same high-temperature annealing and (c) normal wafer surfaces, which underwent just an RCA chemical cleaning before oxidation. Atomic force microscopy (AFM) was performed to reveal the topography of the surfaces. Aluminum pads were deposited on these oxidized surfaces using photolithography techniques. The leakage current through the oxide was measured for all three cases. Our results show that the smoother the surface before oxidation, the smaller the leakage current.

Download Full-text

Two Step O2/N2O Plasma Annealing for the Reduction of Leakage Current in Amorphous Ta2O5 Films

MRS Proceedings ◽

10.1557/proc-567-501 ◽

1999 ◽

Vol 567 ◽

Author(s):

W.S. Lau ◽

M.T. Chandima Perera ◽

T. Han ◽

N. P. Sandler ◽

C.H. Tung ◽

...

Keyword(s):

High Temperature ◽

Low Temperature ◽

Grain Boundaries ◽

Leakage Current ◽

Tantalum Pentoxide ◽

High Temperature Annealing ◽

Voltage Range ◽

Annealing Step ◽

Current Reduction ◽

Plasma Annealing

ABSTRACTAs deposited tantalum pentoxide (Ta2O5) films are amorphous. The films will remain amorphous after O2 or N2O plasma annealing at low temperature. High temperature annealing will produce polycrystalline films where grain boundaries can generate leakage current. Previously, we have shown that N2O plasma annealing is superior to O2 plasma annealing in terms of leakage current reduction for AI/Ta2O5/Si capacitors. However, for TiN/Ta2O5/Si capacitors, the leakage current tends to be higher at low bias voltage for N2O plasma annealing compared to O2 plasma annealing. By adding an 02 plasma annealing step and then comparing TiN/Ta2O5/Si capacitors with two step O2/N2O plasma annealing with respect to similar structures with two step O2/O2 plasma annealing, it can be easily seen that TiN/Ta2O5/Si capacitors with two step O2/N2O plasma annealing have lower leakage current compared to similar structures with two step O2/O2 plasma annealing throughtout the voltage range tested.

Download Full-text

Defect reduction in oxygen implanted silicon-on-insulator material during high-temperature annealing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154998 ◽

1989 ◽

Vol 47 ◽

pp. 604-605

Author(s):

P. Roitman ◽

B. Cordts ◽

S. Visitserngtrakul ◽

S.J. Krause

Keyword(s):

High Temperature ◽

Annealing Temperature ◽

Silicon On Insulator ◽

High Dose ◽

High Temperature Annealing ◽

High Current ◽

Defect Reduction ◽

Annealing Step ◽

Multiple Cycle ◽

Defect Densities

Synthesis of a thin, buried dielectric layer to form a silicon-on-insulator (SOI) material by high dose oxygen implantation (SIMOX – Separation by IMplanted Oxygen) is becoming an important technology due to the advent of high current (200 mA) oxygen implanters. Recently, reductions in defect densities from 109 cm−2 down to 107 cm−2 or less have been reported. They were achieved with a final high temperature annealing step (1300°C – 1400°C) in conjunction with: a) high temperature implantation or; b) channeling implantation or; c) multiple cycle implantation. However, the processes and conditions for reduction and elimination of precipitates and defects during high temperature annealing are not well understood. In this work we have studied the effect of annealing temperature on defect and precipitate reduction for SIMOX samples which were processed first with high temperature, high current implantation followed by high temperature annealing.

Download Full-text

Simulation of the Process of Creation of Thin Silicide Films on Silicon under High-temperature Annealing

Journal of Automation and Information Sciences ◽

10.1615/jautomatinfscien.v33.i1.50 ◽

2001 ◽

Vol 33 (1) ◽

pp. 7

Author(s):

Ivan S. Levchenko ◽

Anatoliy A. Sukennyk ◽

Georgiy A. Chechko

Keyword(s):

High Temperature ◽

High Temperature Annealing

Download Full-text

FERROPERM

Alloy Digest ◽

10.31399/asm.ad.fe0099 ◽

1993 ◽

Vol 42 (4) ◽

Keyword(s):

Fracture Toughness ◽

High Temperature ◽

Physical Properties ◽

Saturation Magnetization ◽

Pure Iron ◽

Magnetic Alloy ◽

High Saturation Magnetization ◽

High Temperature Annealing ◽

Soft Magnetic ◽

Soft Magnetic Alloy

Abstract Ferroperm is a soft magnetic alloy that contains 1% aluminum. This addition of aluminum combined with high-temperature annealing increases permeability and reduces coercivity without decreasing the high-saturation magnetization of pure iron. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming. Filing Code: FE-99. Producer or source: NKK Corporation.

Download Full-text