Hydrogen plasma etching of amorphous and microcrystalline silicon

1987 ◽  
Vol 23 (18) ◽  
pp. 967 ◽  
Author(s):  
R.C. van Oort ◽  
M.J. Geerts ◽  
J.C. van den Heuvel ◽  
J.W. Metselaar
1989 ◽  
Vol 164 ◽  
Author(s):  
M.J. Geerts ◽  
R.C. van Oort ◽  
J.C. van den Heuvel

AbstractIn hydrogenated amorphous silicon NMR studies indicate a twophase structural inhomogenity. Hydrogenated microcrystalline films consist of small crystals with a typical size of 100 Å, embedded in an amorphous web. A hydrogen rf plasma is able to etch both type of films, but with different etch rates. The more crystalline parts of a film are etched more slowly, which makes hydrogen plasma etching a technique that can reveal structural inhomogenities and differences in structural disorder as present, both in amorphous and in microcrystalline silicon films.Amorphous and microcrystalline films were etched and fractal-like structures were visible when using a SEM at a magnification of 20000 times. In microcrystalline films the fractals form a closed network. The number and typical size of the fractals present in amorphous films can be influenced by the conditions during the deposition.


2003 ◽  
Vol 762 ◽  
Author(s):  
C. Smit ◽  
D.L. Williamson ◽  
M.C.M. van de Sanden ◽  
R.A.C.M.M. van Swaaij

AbstractExpanding thermal plasma CVD (ETP CVD) has been used to deposit thin microcrystalline silicon films. In this study we varied the position at which the silane is injected in the expanding hydrogen plasma: relatively far from the substrate and close to the plasma source, giving a long interaction time of the plasma with the silane, and close to the substrate, resulting in a short interaction time. The material structure is studied extensively. The crystalline fractions as obtained from Raman spectroscopy as well as from X-ray diffraction (XRD) vary from 0 to 67%. The average particle sizes vary from 6 to 17 nm as estimated from the (111) XRD peak using the Scherrer formula. Small angle X-ray scattering (SAXS) and flotation density measurements indicate void volume fractions of about 4 to 6%. When the samples are tilted the SAXS signal is lower than for the untilted case, indicating elongated objects parallel to the growth direction in the films. We show that the material properties are influenced by the position of silane injection in the reactor, indicating a change in the plasma chemistry.


2003 ◽  
Vol 762 ◽  
Author(s):  
A. Gordijn ◽  
J.K. Rath ◽  
R.E.I. Schropp

AbstractDue to the high temperatures used for high deposition rate microcrystalline (μc-Si:H) and polycrystalline silicon, there is a need for compact and temperature-stable doped layers. In this study we report on films grown by the layer-by-layer method (LbL) using VHF PECVD. Growth of an amorphous silicon layer is alternated by a hydrogen plasma treatment. In LbL, the surface reactions are separated time-wise from the nucleation in the bulk. We observed that it is possible to incorporate dopant atoms in the layer, without disturbing the nucleation. Even at high substrate temperatures (up to 400°C) doped layers can be made microcrystalline. At these temperatures, in the continuous wave case, crystallinity is hindered, which is generally attributed to the out-diffusion of hydrogen from the surface and the presence of impurities (dopants).We observe that the parameter window for the treatment time for p-layers is smaller compared to n-layers. Moreover we observe that for high temperatures, the nucleation of p-layers is more adversely affected than for n-layers. Thin, doped layers have been structurally, optically and electrically characterized. The best n-layer made at 400°C, with a thickness of only 31 nm, had an activation energy of 0.056 eV and a dark conductivity of 2.7 S/cm, while the best p-layer made at 350°C, with a thickness of 29 nm, had an activation energy of 0.11 V and a dark conductivity of 0.1 S/cm. The suitability of these high temperature n-layers has been demonstrated in an n-i-p microcrystalline silicon solar cell with an unoptimized μc-Si:H i-layer deposited at 250°C and without buffer. The Voc of the cell is 0.48 V and the fill factor is 70 %.


2002 ◽  
Vol 722 ◽  
Author(s):  
Maria Losurdo ◽  
MariaMichela Giangregorio ◽  
Pio Capezzuto ◽  
Giovanni Bruno ◽  
Gon Namkoong ◽  
...  

AbstractThe use of dry hydrogen plasma etching is evaluated for determination of GaN polarity and critically compared to wet etching in NaOH. It is shown that hydrogen plasma etching is effective in revealing inversion domains (IDs) and some types of dislocations. This is because the surface morphology is unchanged by the hydrogen treatment, and, hence, the surface reactivity is not masked.


2000 ◽  
Vol 88 (10) ◽  
pp. 5597-5604 ◽  
Author(s):  
P. Reinke ◽  
P. Oelhafen ◽  
H. Feldermann ◽  
C. Ronning ◽  
H. Hofsäss

2018 ◽  
Vol 455 ◽  
pp. 1179-1184 ◽  
Author(s):  
Leonardo M. Leidens ◽  
Ângela E. Crespi ◽  
Carla D. Boeira ◽  
Fernando G. Echeverrigaray ◽  
Carlos A. Figueroa

2019 ◽  
Vol 123 (36) ◽  
pp. 22665-22673 ◽  
Author(s):  
Tomohiro Matsui ◽  
Hideki Sato ◽  
Kazuma Kita ◽  
André E. B. Amend ◽  
Hiroshi Fukuyama

1998 ◽  
Vol 507 ◽  
Author(s):  
S. Hamma ◽  
D. Colliquet ◽  
P. Rocai Cabarrocas

ABSTRACTMicrocrystalline silicon films were deposited on corning glass substrates both by the standard hydrogen dilution and the layer-by-layer (LBL) technique. In-situ UV-visible spectroscopic ellipsometry measurements were performed to analyze the evolution of the composition of the films.The change of the hydrogen plasma conditions by increasing the pressure in the LBL process leads to a faster kinetic of crystallization and to an increase of the deposition rate by a factor of two. The increase of the pressure and the decrease of the inter-electrode distance allowed to increase the deposition rate from 0.26 to 3 Å/s in the hydrogen dilution technique. Interestingly enough, the crystalline fraction of the films remains higher than 50%. However, as the deposition rate increases the growth process results in a slower kinetic of crystallization with a long range evolution of the film composition (up to 0.5 νm).


1991 ◽  
Vol 219 ◽  
Author(s):  
Y. S. Tsuo ◽  
Y. Xu ◽  
D. W. Baker ◽  
S.K Deb

ABSTRACTWe have studied wet-chemical and dry etching properties of doped and undoped hydrogenated amorphous silicon (a-Si:H) films with bonded hydrogen content varying from 0 to 20 at.%. Etching processes studied include (1) wet-chemical etching using solutions of KOH, isopropyl alcohol (IPA), and H2O, (2) hydrogen plasma etching, and (3) XeF2 vapor etching.


Sign in / Sign up

Export Citation Format

Share Document