Substrate Interactions in the Formation of Amorphous Silicon/Dielectric Interfaces

1989 ◽  
Vol 149 ◽  
Author(s):  
G. N. Parsons ◽  
S. S. Kim ◽  
G. Lucovsky

ABSTRACTUsing Remote PECVD we have deposited layers of “device quality” a-Si:H and Si-based dielectrics. We find that the formation of depletion or accumulation layers at a-Si:H/dielectric interface depends on the specific dielectric (SiO2 or Si3N4) and on the film deposition sequence. In addition, we have studied process-gas/substrate interactions by in-situ Auger Electron Spectroscopy (AES) and determined that Si-O or Si-N bonds are produced at a-Si and c-Si surfaces exposed to plasma excited He/O2, or NH3 mixtures, respectively. These process-gas/substrate interactions occur in parallel with film deposition and are correlated with the electronic properties of the interfaces, and the layer deposition sequence.

1986 ◽  
Vol 71 ◽  
Author(s):  
C. M. Gronet ◽  
C. A. King ◽  
J. F. Gibbons

AbstractSiGe/Si superlattices were grown using limited reaction processing in a chamber which allows both W-halogen and Hg arc wafer illumination. Each multilayer structure was fabricated in-situ by changing the gas composition between high temperature cycles. Commensurate SiGe alloy layers as thin as 15 nm were reproducibly deposited and were examined using transmission electron microscopy, sputtering Auger electron spectroscopy,and Rutherford backscattering. Preliminary results are presented on UV/ozone cleaning of LRP substrates to remove residual carbon contamination in-situ prior to film deposition.


2006 ◽  
Vol 326-328 ◽  
pp. 689-692
Author(s):  
Seung Jae Moon

The thermal conductivity of amorphous silicon (a-Si) thin films is determined by using the non-intrusive, in-situ optical transmission measurement. The thermal conductivity of a-Si is a key parameter in understanding the mechanism of the recrystallization of polysilicon (p-Si) during the laser annealing process to fabricate the thin film transistors with uniform characteristics which are used as switches in the active matrix liquid crystal displays. Since it is well known that the physical properties are dependent on the process parameters of the thin film deposition process, the thermal conductivity should be measured. The temperature dependence of the film complex refractive index is determined by spectroscopic ellipsometry. A nanosecond KrF excimer laser at the wavelength of 248 nm is used to raise the temperature of the thin films without melting of the thin film. In-situ transmission signal is obtained during the heating process. The acquired transmission signal is fitted with predictions obtained by coupling conductive heat transfer with multi-layer thin film optics in the optical transmission measurement.


1998 ◽  
Vol 525 ◽  
Author(s):  
B. Claflin ◽  
M. Binger ◽  
G. Lucovsky

ABSTRACTThe chemical stability of the compound metals TiNx and WNx on SiO2 and SiO2/Si3N4 (ON) dielectric stacks is studied by on-line Auger electron spectroscopy (AES) following sequential rapid thermal annealing treatments of 15 - 180 s up to 850 °C. The TiNx/SiO2 interface reacts at 850 °C and the reaction is kinetics driven. The TiNx/Si3N4 interface is more stable than TiNx/SiO2 even after a 180 s anneal at 850 °C. WNx is stable below 650 °C both on SiO2 and Si3N4, but above this temperature the film changes, possibly due to crystallization or interdiffusion. The changes in the WNx film are not controlled by kinetics. The compound metals are chemically more stable at elevated temperatures than pure Ti or W on SiO2.


2000 ◽  
Vol 612 ◽  
Author(s):  
J. S. Pan ◽  
A. T. S. Wee ◽  
C. H. A. Huan ◽  
J. W. Chai ◽  
J. H. Zhang

AbstractTantalum (Ta) thin films of 35 nm thickness were investigated as diffusion barriers as well as adhesion-promoting layers between Cu and SiO2 using X-ray diffractometry (XRD), Scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). After annealing at 600°C for 1h in vacuum, no evidence of interdiffusion was observed. However, XPS depth profiling indicates that elemental Si appears at the Ta/SiO2 interface after annealing. In-situ XPS studies show that the Ta/SiO2 interface was stable until 500°C, but about 32% of the interfacial SiO2 was reduced to elemental Si at 600°C. Upon cooling to room temperature, some elemental Si recombined to form SiO2 again, leaving only 6.5% elemental Si. Comparative studies on the interface chemical states of Cu/SiO2 and Ta/SiO2 indicate that the stability of the Cu/Ta/SiO2/Si system may be ascribed to the strong bonding of Ta and SiO2, due to the reduction of SiO2 through Ta oxide formation.


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