Chamber pressure

About: Chamber pressure is a research topic. Over the lifetime, 2988 publications have been published within this topic receiving 30725 citations.

Deep etch of GaP using high-density plasma for light-emitting diode applications

Abstract: Deep etching of GaP was performed by high-density plasma using an inductively coupled plasma (ICP) etcher. The effects of process parameters such as the gas combination (Cl2/N2), chamber pressure, inductive power and rf chuck power were investigated. The dependences of the etch rates and selectivity on the rf chunk power and chamber pressure were studied using the response surface method. The results obtained can be further interpreted by the plasma properties (ion flux and dc bias) measured in situ by a Langmuir probe. With an increase in the chamber pressure to 4 Pa, a maximum etch rate of ∼7.5 μm/min for GaP can be obtained under a Cl2/(Cl2+N2) gas mixture of 0.8, ICP power of 800 W, and rf power of 100 W. The increase in the etch rate with an increase in chamber pressure indicates that reactive radicals are the main etching species. To clarify the etching mechanism, the surface reaction of GaP under various Cl2/(Cl2+N2) gas mixtures was investigated by x-ray photoelectron spectroscopy and atomic force...

Sidewall profile control of thick benzocyclobutene reactively ion etched in CF4∕O2 plasmas

Abstract: The feasibility of controlling the sidewall angle of thick benzocyclobutene (BCB) etched in a CF4∕O2 plasma using thick photoresist as an etch mask has been investigated. Sidewall angle, BCB etch rate, and BCB to photoresist selectivity as functions of chamber pressure and CF4 to O2 ratios are reported. Through the use of postdeveloped reflown photoresist, an optimum sidewall angle of less than 60° was achieved at 33mT chamber pressure and a 19% CF4∕O2 ratio. The method presented here achieves deep, residue-free etching of thick BCB with a sidewall profile suitable for e-beam evaporated and lifted metal for use in vertical interconnects.

Indentation fracture of a-C:H thin films from chemical vapour deposition

Abstract: Thin films of a-C:H were produced by chemical vapour deposition from butene and butadiene gases on silicon. Hardness, elastic modulus and residual stress of the films vary depending on the voltage bias and chamber pressure during deposition. Films obtained with voltage bias of −200 V and chamber pressure of 8 Pa for the two precursor gases were analyzed. Film thicknesses were about 900 nm and hardness was 6.6 GPa for film from butadiene gas and 7.9 GPa for butene gas. Cube-corner and Berkovich indenters were used to produce indentation fracture on these films. Crack initiation, delamination and chipping were correlated to modifications of load versus displacement curves. Fractography of cracks was made by scanning electron microscopy and atomic force microscopy. Cracks generated by indentation with cube-corner and Berkovich indenters were compared. Delamination could be analyzed from the derivative of load versus displacement curves. Samples that present higher hardness values do not show chipping. Indent...

Some injector element detail effects on screech in hydrogen-oxygen rockets

Abstract: An experimental investigation was conducted to learn more about how the specific details of a concentric tube injection element affect the screech characteristics of a hydrogen-oxygen rocket engine. The four variables investigated were (1) impingement angle, (2) oxidizer tube blunt base thickness, (3) oxidizer tube recess and extension, and (4) oxidizer tube-annulus concentricity. Tests were made using a 27.34-cm (10.77-in.) diameter heat sink combustor at nominally 300-psia chamber pressure. All of the test variables were investigated using a 157 element circular pattern injector. Additional oxidizer tube recess tests were made with a 421 element hexagonal pattern injector. Tests were conducted over the oxidant-fuel ratio range of 4 to 6. Stability evaluation for each configuration was made using the hydrogen temperature rating technique. Several element configurations were also cold flow tested using nitrogen and water as simulants. The element detail changes resulted in changes in hydrogen injector pressure drop even though the physical injection area was constant for all similar tests in both hot firing and cold flow tests. These changes in injector pressure drop produced changes in combustion stability. The data were correlated with a modified version of a previously reported injection area ratio correlation. By interpreting changes in injector pressure drop as changes in injector hydrogen flow resistance, the data were compared with a hydrogen flow response stability model and were found to be in agreement.