¼c Silicon Thin Films Deposited by Remote Plasma Enhanced Chemical Vapor Deposition Process

1990 ◽  
Vol 192 ◽  
Author(s):  
C. Wang ◽  
G. N. Parsons ◽  
S. S. Kim ◽  
E. C. Buehler ◽  
R. J. Nemanich ◽  
...  

ABSTRACTIn an earlier study, we deposited ¼c-Si thin films by reactive magnetron sputtering (RMS). Here we extend our studies to the deposition of both undoped and high conductivity N-type and P-type ¼c-Si thin films by a remote PECVD. We show that ¼c-Si films can be deposited by bringing hydrogen, H2, into the source gas mixtures. The H2 could introduced by either upstream in a He/H2 mixture and directly plasma excited, or downstream, and be remotely excited along with the silane, SiH4, feed gas. The degree of crystallinity is shown to depend on the hydrogen dilution, the substrate temperature and the substrate material.

1990 ◽  
Vol 204 ◽  
Author(s):  
C. Wang ◽  
C.H. Bjorkman ◽  
D.R. Lee ◽  
M.J. Williams ◽  
G. Lucovsky

ABSTRACTWe have succeeded in depositing both activated n- and p-type μc-Si, by a low temperature, 250°C, remote PECVD process in which dopant gases (PH3 or B2H6)/Silane (SiH4) mixtures are injected downstream from the exit port of a He/H2 plasma. The room temperature conductivities and activation energies for the n- and p-type μc-Si are respectively, 40 S/cm with Eaa=0.018 eV, and 5 S/cm with Ea =0.040 eV. Doped μc-Si is obtained for PH3/SiH4 ratios up to 1%, and for B2H6/SiH4 ratios to 0.1%. For B2H6/SiH4 ratios < 0.1%, the deposited p-type material is doped a-Si rather than doped μc-Si. We have shown that these heavily doped μc-Si film are a viable candidate for the gate electrode in MOS devices. The application of these doped μc-Si films in p-i-n diode devices has also been studied.


2009 ◽  
Vol 1153 ◽  
Author(s):  
Yuri Vygranenko ◽  
Ehsanollah Fathi ◽  
Andrei Sazonov ◽  
Manuela Vieira ◽  
Gregory Heiler ◽  
...  

AbstractWe report on structural, electronic, and optical properties of boron-doped, hydrogenated nanocrystalline silicon (nc-Si:H) thin films deposited by plasma-enhanced chemical vapor deposition (PECVD) at a substrate temperature of 150°C. Film properties were studied as a function of trimethylboron-to-silane ratio and film thickness. The film thickness was varied in the range from 14 to 100 nm. The conductivity of 60 nm thick films reached a peak value of 0.07 S/cm at a doping ratio of 1%. As a result of amorphization of the film structure, which was indicated by Raman spectra measurements, any further increase in doping reduced conductivity. We also observed an abrupt increase in conductivity with increasing film thickness ascribed to a percolation cluster composed of silicon nanocrystallites. The absorption loss of 25% at a wavelength of 400 nm was measured for the films with optimized conductivity deposited on glass and glass/ZnO:Al substrates. A low-leakage, blue-enhanced p-i-n photodiode with an nc-Si p-layer was also fabricated and characterized.


1991 ◽  
Vol 219 ◽  
Author(s):  
C. Wang ◽  
G. Lucovsky ◽  
R. J. Nemanich

ABSTRACTWe have extended the remote PECVD process to the deposition of intrinsic and doped, amorphous and microcrystalline silicon, carbon alloy films, a-Si,C:H and μc-Si,C, respectively. The electrical and optical properties of a-Si,C:H deposited by remote PECVD are comparable to those of films deposited by the glow discharge or GD process. The degree of crystallinity in the μc-Si,C alloys, as determined from the relative intensities of crystalline and amorphous features in the Raman spectra, is lower than that of μc-Si films deposited under comparable deposition conditions. The Raman spectra indicate that the crystallites in the μc-Si,C alloys are Si, while the infrared measurements establish that the intervening amorphous component is an a-Si,C:H alloy.


2007 ◽  
Vol 989 ◽  
Author(s):  
Yasutoshi YASHIKI ◽  
Seiichi KOUKETSU ◽  
Shinsuke MIYAJIMA ◽  
Akira YAMADA ◽  
Makoto KONAGAI

AbstractEffects of boron doping on microcrystalline germanium carbon alloy (μc-Ge1-xCx:H) thin films have been investigated. We deposited boron-doped p-type μc-Ge1-xCx:H thin films by hot-wire chemical vapor deposition technique using hydrogen diluted monomethylgermane (MMG) and diborane (B2H6). A dark conductivity of 1.3 S/cm and carrier concentration of 1.7 x 1020 cm-3 were achieved with B2H6/MMG ratio of 0.1. Furthermore, the activation energy decreased from 0.37 to 0.037 eV with increasing B2H6/MMG ratio from 0 to 0.1. We also fabricated p-type μc-Ge1-xCx:H/n-type c-Si heterojunction diodes. The diodes showed rectifying characteristics. The typical ideality factor and rectifying ratio were 1.4 and 3.7 x 103 at ¡Ó 0.5 V, respectively.


2001 ◽  
Vol 685 ◽  
Author(s):  
Y.-G. Yoon ◽  
G.-B. Kim ◽  
H.-H Park ◽  
S.-W Lee ◽  
S.-K. Joo

AbstractWe studied on the effect of a deposition condition of precursor a-Si thin films on the shape and micro-structure of MILC. The a-Si thin films were prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD) with silane and hydrogen as a source gas and the deposition temperature was varied from 100 to 400∼. The a-Si films deposited at a lower temperature showed a tendency to (111) crystals and leaving some a-Si residues in MILC region, while those with higher deposition temperature tended to be crystallized to (110). These differences were explained in terms of original hydrogen content and following structural changes by the dehydrogenation during annealing.


2003 ◽  
Vol 762 ◽  
Author(s):  
H.R. Moutinho ◽  
C.-S. Jiang ◽  
B. Nelson ◽  
Y. Xu ◽  
J. Perkins ◽  
...  

AbstractWe have studied the influence of substrate temperature and hydrogen dilution ratio on the properties of silicon thin films deposited on single-crystal silicon and glass substrates. We varied the initial substrate temperature from 200° to 400°C and the dilution ratio from 10 to 100. We also studied the effectiveness of the use of a seed layer to increase the crystallinity of the films. The films were analyzed by atomic force microscopy, X-ray diffraction, Raman spectroscopy, and transmission and scanning electron microscopy. We found that as the dilution ratio is increased, the films go from amorphous, to a mixture of amorphous and crystalline, to nanocrystalline. The effect of substrate temperature is to increase the amount of crystallinity in the film for a given dilution ratio. We found that the use of a seed layer has limited effects and is important only for low values of dilution ratio and substrate temperature, when the films have large amounts of the amorphous phase.


2007 ◽  
Vol 989 ◽  
Author(s):  
Mahdi Farrokh Baroughi ◽  
Hassan G. El-Gohary ◽  
Cherry Y. Cheng ◽  
Siva Sivoththaman

AbstractHighly conductive epiraxial silicon thin films, with conductivities more than 680 ¥Ø-1cm-1, were obtained using plasma enhanced chemical vapor deposition (PECVD) technique at 300¢ªC. The effect of hydrogen in growth of low temperature extrinsic Si thin films was studied using conductivity, Hall, and Raman measurements, and it was shown that epitaxial growth was possible at hydrogen dilution (HD) ratios more than 85%. The epitaxial growth of the extrinsic Si thin films at high hydrogen dilution regime was confirmed by high resolution transmission electron microscopy (HRTEM).


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