IR and MW Absorption Techniques for Bulk and Surface Recombination Control in High-Quaiity Silicon

1995 ◽  
Vol 386 ◽  
Author(s):  
A. Kaniava ◽  
U. Menczigar ◽  
J. Vanhellemont ◽  
J. Poortmans ◽  
A. L. P. Rotondaro ◽  
...  
Keyword(s):  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Silicon Substrates ◽  
Injection Level ◽  
Effective Lifetime ◽  
Carrier Recombination ◽  
High Injection Level ◽  
High Injection ◽  
Wide Range ◽  
Recombination Velocity

ABSTRACTThe carrier recombination rate in high-quality FZ and Cz silicon substrates is studied by contactless infrared and microwave absorption techniques. Different surface treatments covering a wide range of surface recombination velocity have been used for the separation of bulk and surface recombination components and evaluating of the efficiency of passivation. Limitations of effective lifetime approach are analyzed specific for low and high injection level. Sensitivity limits of the techniques for iron contamination are discussed

Analysis of the Effect of Temperature on Base Current Gain in Power 4H-SiC BJTs

2006 ◽  
Vol 527-529 ◽  
pp. 1441-1444
Author(s):  
Pavel A. Ivanov ◽  
Michael E. Levinshtein ◽  
Anant K. Agarwal ◽  
Sumi Krishnaswami ◽  
John W. Palmour
Keyword(s):  
Elevated Temperatures ◽  
Operation Mode ◽  
Surface Recombination ◽  
Current Gain ◽  
Surface Recombination Velocity ◽  
Effect Of Temperature ◽  
Collector Current ◽  
Carrier Lifetimes ◽  
Wide Range ◽  
Recombination Velocity

For 1-kV, 30-A 4H-SiC epitaxial emitter npn bipolar junction transistors, the dependence of the common-emitter current gain β on the collector current IC were measured at elevated temperatures. The collector-emitter voltage was fixed (at 100 V voltage) to provide an active operation mode at all collector currents varying in a wide range from 150 mA to 40 A (current densities 24 - 6350 A/cm2). The maximum room temperature current gain was measured to be βmax = 40 (IC = 7 A) while βmax = 32 (IC = 10 A) at 250oC. The β-IC dependences were simulated using a model which takes into account the main processes affecting the current gain. Minority carrier lifetimes and surface recombination velocity were obtained by means of those considerations.

scholarly journals Ultrathin Oxide Passivation Layer by Rapid Thermal Oxidation for the Silicon Heterojunction Solar Cell Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Youngseok Lee ◽  
Woongkyo Oh ◽  
Vinh Ai Dao ◽  
Shahzada Qamar Hussain ◽  
Junsin Yi
Keyword(s):  
Solar Cell ◽  
Thermal Oxidation ◽  
Oxide Layer ◽  
Silicon Oxide ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Effective Lifetime ◽  
Silicon Oxide Layer ◽  
Rapid Thermal Oxidation ◽  
Recombination Velocity

It is difficult to deposit extremely thin a-Si:H layer in heterojunction with intrinsic thin layer (HIT) solar cell due to thermal damage and tough process control. This study aims to understand oxide passivation mechanism of silicon surface using rapid thermal oxidation (RTO) process by examining surface effective lifetime and surface recombination velocity. The presence of thin insulating a-Si:H layer is the key to get highVocby lowering the leakage current (I0) which improves the efficiency of HIT solar cell. The ultrathin thermal passivation silicon oxide (SiO2) layer was deposited by RTO system in the temperature range 500–950°C for 2 to 6 minutes. The thickness of the silicon oxide layer was affected by RTO annealing temperature and treatment time. The best value of surface recombination velocity was recorded for the sample treated at a temperature of 850°C for 6 minutes at O2flow rate of 3 Lpm. A surface recombination velocity below 25 cm/s was obtained for the silicon oxide layer of 4 nm thickness. This ultrathin SiO2layer was employed for the fabrication of HIT solar cell structure instead of a-Si:H, (i) layer and the passivation and tunneling effects of the silicon oxide layer were exploited. The photocurrent was decreased with the increase of illumination intensity and SiO2thickness.

scholarly journals Numerical Simulation Analysis of Ag Crystallite Effects on Interface of Front Metal and Silicon in the PERC Solar Cell

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 592
Author(s):  
Myeong Sang Jeong ◽  
Yonghwan Lee ◽  
Ka-Hyun Kim ◽  
Sungjin Choi ◽  
Min Gu Kang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Efficiency ◽  
Open Circuit Voltage ◽  
Surface Recombination ◽  
Open Circuit ◽  
Surface Recombination Velocity ◽  
Metal Interface ◽  
Ag Crystallites ◽  
Recombination Velocity

In the fabrication of crystalline silicon solar cells, the contact properties between the front metal electrode and silicon are one of the most important parameters for achieving high-efficiency, as it is an integral element in the formation of solar cell electrodes. This entails an increase in the surface recombination velocity and a drop in the open-circuit voltage of the solar cell; hence, controlling the recombination velocity at the metal-silicon interface becomes a critical factor in the process. In this study, the distribution of Ag crystallites formed on the silicon-metal interface, the surface recombination velocity in the silicon-metal interface and the resulting changes in the performance of the Passivated Emitter and Rear Contact (PERC) solar cells were analyzed by controlling the firing temperature. The Ag crystallite distribution gradually increased corresponding to a firing temperature increase from 850 ∘C to 950 ∘C. The surface recombination velocity at the silicon-metal interface increased from 353 to 599 cm/s and the open-circuit voltage of the PERC solar cell decreased from 659.7 to 647 mV. Technology Computer-Aided Design (TCAD) simulation was used for detailed analysis on the effect of the surface recombination velocity at the silicon-metal interface on the PERC solar cell performance. Simulations showed that the increase in the distribution of Ag crystallites and surface recombination velocity at the silicon-metal interface played an important role in the decrease of open-circuit voltage of the PERC solar cell at temperatures of 850–900 ∘C, whereas the damage caused by the emitter over fire was determined as the main cause of the voltage drop at 950 ∘C. These results are expected to serve as a steppingstone for further research on improvement in the silicon-metal interface properties of silicon-based solar cells and investigation on high-efficiency solar cells.

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.

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