An intensive study has been performed to understand and tune deep reactive ion etch (DRIE) processes for optimum results with respect to the silicon etch rate, etch profile and mask etch selectivity (in order of priority) using state-of-the-art dual power source DRIE equipment. The
research compares pulsed-mode DRIE processes (e.g. Bosch technique) and mixed-mode DRIE processes (e.g. cryostat technique). In both techniques, an inhibitor is added to
fluorine-based plasma to achieve directional etching, which is formed out of an oxide-forming (O2) or a fluorocarbon (FC) gas (C4F8 or CHF3). The inhibitor can be introduced together with the etch gas, which is named a mixed-mode DRIE process, or the inhibitor can be added in a
time-multiplexed manner, which will be termed a pulsed-mode DRIE process. Next, the most convenient mode of operation found in this study is highlighted including some remarks to
ensure proper etching (i.e. step synchronization in pulsed-mode operation and heat control of the wafer). First of all, for the fabrication ......
 Enjoy reading . Henri Jansen 18 June 2008

https://iopscience.iop.org/article/10.1088/0960-1317/19/3/033001/pdf

Black silicon method X: a review on high speed and selective plasma etching of silicon with profile control: an in-depth comparison between Bosch and cryostat DRIE processes as a roadmap to next generation equipment

A new compound, tris(dimethylamino)silane was used as an organosilicon source for the deposition of silicon oxynitride thin films. The depositions were carried out at low substrate temperatures (<150 °C) in an electron cyclotron resonance plasma enhanced chemical vapor deposition reactor. Films with compositions varying from Si3N4 to SiO2 were deposited on silicon substrates by varying the N2/O2 flow ratio to the plasma chamber. In situ ellipsometry measurements of the film optical index were well correlated with film composition. Auger electron spectroscopy showed that only low levels of carbon (<3 at. %) were present, while Fourier transform infrared spectroscopy showed low levels of bonded hydrogen. The deposition rate of high quality Si3N4 was as high as 220 A/min.

Electron cyclotron resonance chemical vapor deposition of silicon oxynitrides using tris(dimethylamino)silane

The OH(X2Π) radical in a 20:80 tetraethoxysilane (TEOS)/O2 plasmas has been characterized during deposition of SiO2 using the imaging of radicals interacting with surfaces (IRIS) method. The reactivity of OH at the surface of a growing SiO2 film has been determined as a function of the applied radio-frequency (rf) plasma power (P) and the substrate temperature (TS). The reactivity (R) of OH during deposition of SiO2 on a 300 K Si substrate is 0.41 ± 0.04. R decreases as substrate temperature increases but is unaffected by increasing rf power. Translational and rotational temperatures (ϑT and ϑR, respectively) of the OH radical are also determined. For a 20:80 TEOS/O2 plasma (P = 85 W), ϑT = 912 ± 20 K and ϑR = 450 ± 20 K. ϑT is significantly higher than ϑR and increases with increasing rf power. Using isotopically labeled 18O2 as a precursor, the source of the oxygen in OH is identified as the O2 gas, not oxygen from the ethoxy groups on TEOS. With these data, the role of OH in deposition of SiO2 from TEO...

Effects of Plasma Processing Parameters on the Surface Reactivity of OH(X2Π) in Tetraethoxysilane/O2 Plasmas during Deposition of SiO2

Deposition kinetics of silicon dioxide from hexamethyldisilazane and oxygen by PECVD

Hexamethyldisilazane (HMDS) has been used as an organosilicon source for the deposition of dielectric films at low temperatures (200-250° C) by microwave plasma enhanced CVD technique. Hydrogenated films of variable composition of silicon carbonitride, silicon oxynitride and silicon dioxide have been deposited by decomposition of HMDS in the presence of additive gases like NH3, O2 and H2 under different process conditions. Deposited films have been characterized by the measurement of refractive index and buffered HF etch rate, and by the analysis of XPS and infrared transmission spectra. An increase in HMDS partial pressure generally results in the decrease of refractive index. The films show stable C-V characteristics of metal-insulator-semicon-ductor (MIS) capacitors with positive insulator charge density.

Low-temperature deposition of dielectric films by microwave plasma enhanced decomposition of hexamethyldisilazane

Nicollian and Goetzberger's well known integral expression for the equivalent parallel conductance due to interface states G p / ω has been given a simple analytical representation which is valid under the condition that interface potential fluctuation parameter σ > 1.5. Previous methods of conductance analysis based upon numerical and/or graphical construction are provided with alternative analytic relations. The earlier parametric numerical relations like ξ p , f w , f D and ln ( ξ + / ξ − ) vs σ are described very well by analytic expressions in this paper. A new relation is presented to determine interface state time constant from the width of conductance peak. A new method is presented to determine dependence of σ on interface band bending from G p / ω vs bias measurements at just two frequencies. The expedient method of Nicollian, Goetzberger and Lopez utilises the same two curves to determine distribution of interface state density N ss and capture cross section σ p across the band gap. Therefore using the present new method for σ determination and other analytical relations for N ss and σ p determination, the expediency of their method is greatly enhanced. Complete conductance analysis for rapid characterization of the interface is shown to become now a simple straight forward affair, and the amount of data required is also substantially reduced.

R.D.S. Yadava

Papers

Analytic approach to the a.c. conductance method for rapid characterization of interface states in MOS structures