scholarly journals Iodine–Ethanol Surface Passivation for Measurement of Millisecond Carrier Lifetimes in Silicon Wafers with Different Crystallographic Orientations

2019 ◽  
Vol 216 (17) ◽  
pp. 1900257 ◽  
Author(s):  
Mohammad Al-Amin ◽  
Nicholas E. Grant ◽  
Alex I. Pointon ◽  
John D. Murphy
Keyword(s):  
Surface Passivation ◽  
Silicon Wafers ◽  
Carrier Lifetimes ◽  
Crystallographic Orientations

KOH-ETCH Related Defects on Processed Silicon Wafers

1992 ◽  
Vol 259 ◽  
Author(s):  
Laurent E. Kassel
Keyword(s):  
Thermal Treatment ◽  
Epitaxial Growth ◽  
Silicon Wafers ◽  
Processing Steps ◽  
Crystallographic Orientations

ABSTRACTKOH, an anisotropic etchant of monocrystalline Si, may cause roughness and defects whose shapes are related to crystallographic orientations. This paper studies the effect of processing steps on the formation of geometric etch defects. Implantation, thermal treatment, epitaxial growth or photoresist were not the source of such defects. In the scope of this study, only unwanted damage caused geometric etch defects. This makes the observation of the wafer after KOH etch a good indicator of the quality of previous steps.

Enhancement of Carrier Lifetimes in n-Type 4H-SiC Epitaxial Layers by Improved Surface Passivation

2010 ◽  
Vol 3 (12) ◽  
pp. 121201 ◽  
Author(s):  
Tsunenobu Kimoto ◽  
Yuichiro Nanen ◽  
Toshihiko Hayashi ◽  
Jun Suda
Keyword(s):  
Surface Passivation ◽  
Epitaxial Layers ◽  
Carrier Lifetimes

Kerfless epitaxial silicon wafers with 7 ms carrier lifetimes and a wide lift-off process window

2018 ◽  
Vol 57 (4) ◽  
pp. 041301 ◽  
Author(s):  
Catherin Gemmel ◽  
Jan Hensen ◽  
Lasse David ◽  
Sarah Kajari-Schröder ◽  
Rolf Brendel
Keyword(s):  
Silicon Wafers ◽  
Process Window ◽  
Epitaxial Silicon ◽  
Carrier Lifetimes ◽  
Lift Off

scholarly journals High efficiency photomodulators for millimeter wave and THz radiation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
I. R. Hooper ◽  
N. E. Grant ◽  
L. E. Barr ◽  
S. M. Hornett ◽  
J. D. Murphy ◽  
...  
Keyword(s):  
High Efficiency ◽  
Continuous Wave ◽  
Broad Band ◽  
Cost Effective ◽  
Silicon Wafers ◽  
Thz Radiation ◽  
Limiting Factor ◽  
Switching Speed ◽  
Carrier Lifetimes ◽  
Narrow Frequency Band

AbstractPhotomodulators for mm-wave and THz radiation are an essential component for many imaging and signal processing applications. While a myriad of schemes have been devised to enhance photomodulation by enhancing the light-matter interaction, there has been less focus on the photoconductive materials themselves, which are often the limiting factor. Here, we present an approach to increase the photomodulation efficiency of silicon by orders of magnitude, using post treatment of off-the-shelf silicon wafers. The increase in efficiency removes the need for bulky and costly amplified laser sources, and creates the potential for compact and cost-effective modulators for real-world applications. By passivating the surfaces of long bulk-lifetime silicon wafers with Al2O3, the recombination of the photoexcited carriers at the surfaces is mostly eliminated. This results in vastly longer excess carrier lifetimes (up to ~50 ms), with corresponding increases in photoconductivity. The resulting modulators are highly efficient, with the transmission through them being reduced from ~90% to <10% over a narrow frequency band with a continuous wave excitation intensity of just 10 Wm−2, whilst modulation factors of greater than 80% can be achieved over a broad band with similar intensities. We also discuss the limitations of such long-lifetime modulators for applications where the switching speed or spatial resolution of a modulator may be critical.

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

Long Carrier Lifetimes in n-Type 4H-SiC Epilayers

2012 ◽  
Vol 717-720 ◽  
pp. 279-284 ◽  
Author(s):  
Paul B. Klein
Keyword(s):  
Solid State ◽  
High Voltage ◽  
High Power ◽  
Surface Passivation ◽  
Surface Recombination ◽  
Carrier Lifetimes ◽  
State Switching ◽  
Long Lifetime ◽  
Very High ◽  
Thick Layers

Recent advances in preparing n-type 4H-SiC with long carrier lifetimes have greatly enhanced the possibility of realizing commercially available, very high voltage and high power solid state switching diodes. For the range > several kV, vertical bipolar structures are required with drift layers exhibiting carrier lifetimes ≥ several µsec. Recently, low-doped epilayers with carrier lifetimes in excess of this have been demonstrated, thus approaching a goal that has been pursued for over a decade. Historically, the short lifetimes in early epitaxial layers (a few hundred nsec) were eventually identified with the Vc-related Z1/2 lifetime killer. Current strategies to minimize this defect are an essential ingredient in the procedure for obtaining long-lifetime material. In order to optimize the attainable lifetimes, it has been shown that in addition to low Z1/2 levels, very thick layers are required to minimize the effects of recombination in the substrate and surface passivation is also necessary to minimize surface recombination (S < 1000 cm/sec).

Sign in / Sign up

Export Citation Format

Share Document