Surface Recombination Investigation in Thin 4H-SiC Layers

1970 ◽  
Vol 17 (2) ◽  
pp. 119-124 ◽  
Author(s):  
Karolis GULBINAS ◽  
Vytautas GRIVICKAS ◽  
Haniyeh P. MAHABADI ◽  
Muhammad USMAN ◽  
Anders HALLÉN
Keyword(s):  
Surface Passivation ◽  
Surface Recombination ◽  
Atomic Layer ◽  
Surface Recombination Velocity ◽  
Lifetime Distributions ◽  
Carrier Lifetimes ◽  
Layer Deposition ◽  
Type Layer ◽  
Recombination Velocity ◽  
P Type

n- and p-type 4H-SiC epilayers were grown on heavily doped SiC substrates. The thickness of the p-type layer was 7 µm and the doping level around 1017 cm 3, while the n-type epilayers were 15 µm thick and had a doping concentration of 3 - 5*1015 cm 3. Several different surface treatments were then applied on the epilayers for surface passivation: SiO2 growth, Al2O3 deposited by atomic layer deposition, and Ar-ion implantation. Using collinear pump - probe technique the effective carrier lifetimes were measured from various places and statistical lifetime distributions were obtained. For surface recombination evaluation, two models are presented. One states that surface recombination velocity (SRV) is equal on both the passivation/epi layer interface (S2) and the deeper interface between the epilayer and the SiC substrate i. e. (S1 = S2). The other model is simulated assuming that SRV in the epilayer/substrate (S1) interface is constant while in the passivation layer/epilayer (S2) interface SRV can be varied S2 < S1. Empirical nomograms are presented with various parameters sets to evaluate S2 values. We found that on the investigated 4H-SiC surfaces S2 ranges from 3x104 to 5x104 assuming that the bulk lifetime is 4 (µs. In Ar+ implanted surfaces S2 is between (105 - 106) cm/s.http://dx.doi.org/10.5755/j01.ms.17.2.479

scholarly journals Surface passivation of germanium by atomic layer deposited Al2O3 nanolayers

2021 ◽  
Author(s):  
Wilhelmus J. H. Berghuis ◽  
Jimmy Melskens ◽  
Bart Macco ◽  
Roel J. Theeuwes ◽  
Marcel A. Verheijen ◽  
...  
Keyword(s):  
Surface Passivation ◽  
Surface Recombination ◽  
Atomic Layer ◽  
Extensive Study ◽  
Surface Recombination Velocity ◽  
Interface Charges ◽  
Layer Deposition ◽  
Recombination Velocity ◽  
Electronic Defects

AbstractSurfaces of semiconductors are notorious for the presence of electronic defects such that passivation approaches are required for optimal performance of (opto)electronic devices. For Ge, thin films of Al2O3 prepared by atomic layer deposition (ALD) can induce surface passivation; however, no extensive study on the effect of the Al2O3 process parameters has been reported. In this work we have investigated the influence of the Al2O3 thickness (1–44 nm), substrate temperature (50–350 °C), and post-deposition anneal (in N2, up to 600 °C). We demonstrated that an effective surface recombination velocity as low as 170 cm s−1 can be achieved. The role of the GeOx interlayer as well as the presence of interface charges was addressed and a fixed charge density $${Q}_{\mathrm{f}}=$$ Q f = −(1.8 ± 0.5) × 1012 cm−2 has been found. The similarities and differences between the passivation of Ge and Si surfaces by ALD Al2O3 prepared under the same conditions are discussed. Graphic Abstract

Comparison of Efficiencies of Different Surface Passivations Applied to Crystalline Silicon

2005 ◽  
Vol 108-109 ◽  
pp. 585-590 ◽  
Author(s):  
Olivier Palais ◽  
Mustapha Lemiti ◽  
Jean-Francois Lelievre ◽  
Santo Martinuzzi
Keyword(s):  
Silicon Surface ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Phosphorus Diffusion ◽  
Type Silicon ◽  
Good Surface ◽  
Recombination Velocity ◽  
P Type

In this work the efficiencies of different surface passivation techniques are compared. This paper emphasizes on the passivation provided by SiNx:H layers that is commonly used in photovolaic industry as surface passivation and anti reflection layer. The method used to evaluate the surface recombination velocity is detailed and discussed. It is shown that light phosphorus diffusion at 850°C – 20 min provides good surface passivation of n-type silicon surface and noticeable passivation of p-type, that can be improved by SiNx:H Layer.

Investigation of Surface Passivation in InAs/GaSb Strained-Layer-Superlattices Using Picosecond Excitation Correlation Measurement and Variable-Area Diode Array Surface Recombination Velocity Measurement

2005 ◽  
Vol 891 ◽  
Author(s):  
Zhimei Zhu ◽  
Elena Plis ◽  
Abdenour Amtout ◽  
Pallab Bhattacharya ◽  
Sanjay Krishna
Keyword(s):  
Infrared Detectors ◽  
Surface Passivation ◽  
Surface Recombination ◽  
Surface States ◽  
Depletion Region ◽  
Surface Recombination Velocity ◽  
Diode Array ◽  
Ammonium Sulfide ◽  
Picosecond Excitation ◽  
Recombination Velocity

ABSTRACTThe effect of ammonium sulfide passivation on InAs/GaSb superlattice infrared detectors was investigated using two complementary techniques, namely, picosecond excitation correlation (PEC) measurement and variable-area diode array (VADA) surface recombination velocity (SRV) measurement. PEC measurements were conducted on etched InAs/GaSb superlattice mesas, which were passivated in aqueous ammonium sulfide solutions of various strengths for several durations. The PEC signal's decay time constant (DTC) is proportional to carrier lifetimes. At 77 K the PEC signal's DTC of the as-grown InAs/GaSb superlattice sample was 2.0 ns, while that of the unpassivated etched sample was reduced to 1.2 ns by the surface states at the mesa sidewalls. The most effective ammonium sulfide passivation process increased the PEC signal's DTC to 10.4 ns. However it is difficult to isolate surface recombination from other processes that contribute to the lifetime using the PEC data, therefore a VADA SRV measurement was undertaken to determine the effect of passivation on surface recombination. The obtained SRV in the depletion region of the InAs/GaSb superlattice and GaSb junction was 1.1×106 cm/s for the unpassivated sample and 4.6×105 cm/s for the passivated sample. At 77 K the highest R0A value measured in our passivated devices was 2540 W cm2 versus 0.22 W cm2 for the unpassivated diodes. The results of the lifetime, the SRV and the R0A measurements indicate that ammonium sulfide passivation will improve the performance of InAs/GaSb superlattice infrared detectors.

Single material TiO 2 thin film by atomic layer deposition for antireflection and surface passivation applications on p-type c-Si

2018 ◽  
Vol 451 ◽  
pp. 121-127 ◽  
Author(s):  
Tsung-Cheng Chen ◽  
Tsuo-Chuan Yang ◽  
Hsyi-En Cheng ◽  
Ing-Song Yu ◽  
Zu-Po Yang
Keyword(s):  
Thin Film ◽  
Atomic Layer Deposition ◽  
Surface Passivation ◽  
Atomic Layer ◽  
Layer Deposition ◽  
Type C ◽  
P Type ◽  
Single Material

Optimization of the Specific On-Resistance of 4H-SiC BJTs

2006 ◽  
Vol 527-529 ◽  
pp. 1429-1432 ◽  
Author(s):  
S. Balachandran ◽  
T. Paul Chow ◽  
Anant K. Agarwal
Keyword(s):  
High Voltage ◽  
Minority Carrier ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Bipolar Junction Transistors ◽  
Carrier Lifetimes ◽  
Minority Carrier Lifetimes ◽  
Recombination Velocity ◽  
The Impact

We evaluate the performance capabilities and limitations of high voltage 4H-SiC based Bipolar Junction Transistors (BJTs). Experimental forward characteristics of a 4kV BJT are studied and simulations are employed to determine the factors behind the higher than expected specific onresistance (Ron,sp) for the device. The impact of material (minority carrier lifetimes), processing (surface recombination velocity) and design (p contact spacing from the emitter mesa) parameters on the forward active performance of this device are discussed and ways to lower Ron,sp, below the unipolar level, and increase the gain (β) are examined.

Orientation Dependence Of Surface Passivation For Semi-Insulating Gaas

1996 ◽  
Vol 421 ◽  
Author(s):  
I.P. Koutzarov ◽  
C.H. Edirisinghe ◽  
H.E. Ruda ◽  
L.Z. Jedral ◽  
Q. Liu ◽  
...  
Keyword(s):  
Band Gap ◽  
Surface Passivation ◽  
Dielectric Film ◽  
Surface Recombination ◽  
Orientation Dependence ◽  
Film Deposition ◽  
Surface Recombination Velocity ◽  
Strong Increase ◽  
X Ray ◽  
Recombination Velocity

AbstractWe report on the orientation dependence ((100), (110) and (111) ) of photoluminescence (PL), photoreflectance (PR) and Surface Photo-Voltage (SPV) for sulfur passivated bulk semiinsulating (SI) GaAs. Near band gap PL peak intensities (bound-exciton and acceptor-related) were enhanced following (NH4)2S or S2Cl2 treatment of GaAs for all orientations. The reduction of surface recombination velocity (from PL data) was orientation dependent and especially pronounced for the case of (111)A and (111)B orientations. The effect of thin dielectric layers deposited on S-treated surfaces was also investigated, particularly for (100) and (111)A orientations. SPV data shows a strong increase in the above band gap signal after both Streatment and dielectric film deposition, which was higher than that measured for only S-treated surfaces. PR data showed an increase in the interfacial electric field following deposition of dielectric film. The results of absolute S-surface coverage measurements using particle-induced X-ray emission measurements were correlated with the optical characteristics.

Scanning-laser-microscope measurements of minority-carrier diffusion length and surface recombination velocity in polycrystalline silicon

1985 ◽  
Vol 63 (6) ◽  
pp. 870-875 ◽  
Author(s):  
S. Damaskinos ◽  
A. E. Dixon
Keyword(s):  
Polycrystalline Silicon ◽  
Minority Carrier ◽  
Surface Recombination ◽  
Beam Intensity ◽  
Scanning Laser ◽  
Surface Recombination Velocity ◽  
Minority Carrier Diffusion Length ◽  
Spatially Resolved ◽  
Recombination Velocity ◽  
P Type

A scanning laser microscope was used to study the electronic and recombination properties at grain boundaries of both n- and p-type Wacker polycrystalline silicon in a spatially resolved photoconductivity experiment. The light energy falling on the samples was varied over five orders of magnitude from 10−1 to 10−6 mW. For p-type material the measured L decreased with beam intensity from 150 to 60 μm, reaching a constant value at very low beam intensities. The small focal spot of the microscope allowed the measurements to be extended to include n-type samples. Forthese samples L was found to change from 90 to 18 μm with decreasing beam intensity. The surface recombination velocity SGB was evaluated for both samples. For p-type samples it decreased from 25 000 to 6000 cm/s and for n-type samples from 21 000 to 3000 cm/s with decreasing beam intensity. The quasi-Fermi level separation was determined as a function of the excess minority-carrier-concentration density at the grain boundary and found to increase linearly with beam intensity.

Forward Active and Blocking Performance of 4H-SiC Bipolar Junction Transistors

2005 ◽  
Vol 888 ◽  
Author(s):  
Santhosh Balachandran ◽  
T. Paul Chow ◽  
Anant Agarwal
Keyword(s):  
High Voltage ◽  
Minority Carrier ◽  
Surface Recombination ◽  
Current Gain ◽  
Surface Recombination Velocity ◽  
Bipolar Junction Transistors ◽  
Carrier Lifetimes ◽  
Minority Carrier Lifetimes ◽  
Recombination Velocity ◽  
The Impact

ABSTRACTWe evaluate the performance capabilities and limitations of high voltage 4H-SiC based Bipolar Junction Transistors (BJTs). Experimental forward characteristics of a 4kV BJT are studied and simulations are employed to determine the factors behind the higher than expected specific on-resistance (Ron,sp) for the device. The impact of material (minority carrier lifetimes), processing (surface recombination velocity) and design (p contact spacing from the emitter mesa) parameters on the forward active performance of this device are discussed and ways to lower Ron,sp, below the unipolar level, and increase the gain (β) are examined. A correlation between the open base blocking behavior (forward blocking) and the current gain (forward active) for 4H-SiC based high-voltage BJTs with lightly doped collector regions is presented and experimental device characteristics are utilized to verify our numerical analysis.

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