Abstract:
PROBLEM TO BE SOLVED: To etch a pattern in the metallic silicide film within composite material by bringing the metallic silicide film into contact with the plasma being created by the mixed gas flow of HCl and Cl2 where the flow ratio HCl:Cl2 is set in the specified range. SOLUTION: The etching process includes etching a metallic silicide layer at a higher rate than that of the polysilicon layer within the composite material of the metallic silicide and polysilicon, and in this etching process, the metallic silicide film is brought into contact with the plasma being created by the mixed gas flow of HCl and Cl2 where the volume flow ratio HCl:Cl2 is set in the range of 3:1 to 6:1. Hereby, the pattern within the metallic silicide layer within the composite material of metallic silicide and polysilicon can be etched.
Abstract:
PROBLEM TO BE SOLVED: To check cracks within a final passivation laver 13 of an integrated circuit by reducing the stresses within a peripheral dielectric which are due to acute corner of a circuit pattern. SOLUTION: Stresses generally induced inside a dielectric is reduced by formings 15 and 17, at lower corner 14" of a circuit pattern 11 before adhering an outer layer (that is, a passivation layer) 13. When patterning it by metallic RIE process, this kind of rounding of the corner is achieved by a two-step metallic etching process, including the first step of creating a vertical sidewall and the second step of tapering the lower part of the vertical sidewall or creating a tapered spacer 15 along the under section of the vertical sidewall. When patterning it by a die machine process, this kind of rounding of the corner is achieved by a two-step trench etching process, including a first step of creating a vertical sidewall and a second step of creating a tapered side wall along the under section of the vertical sidewall. COPYRIGHT: (C)1999,JPO
Abstract:
Metal silicide is removed at a faster rate than polysilicon in dry etching of metal silicide/polysilicon composites with an etching gas made from HCl and Cl2 at a volumetric flowrate ratio of HCl:Cl2 within the range of 3:1 to 5:1.
Abstract:
A process for forming the ridge structure of a self-aligned semiconductor laser, particularly useful for long wavelength devices as required for signal transmission systems. Described is the process as applied to an InP-system, double heterostructure (DH) laser. A thin Si3N4 layer (41) is inserted between the photoresist mask (42) that defines the ridge structure, and the contact layer (35). This results in improved adhesion and reduced etch undercutting whereby the ohmic contact area is increased, heat development decreased and device properties improved. Using a Si3N4 layer (41) deposited at a high plasma excitation frequency (RF) for adhesion promotion, and a low frequency deposited (LF) Si3N4 layer (43) for device embedding, provides for the etch selectivity required in the process stepthat is used to expose the contact layer to ohmic contact metallization deposition.
Abstract:
METHOD FOR PASSIVATING A COMPOUND SEMICONDUCTOR SURFACE AND DEVICE HAVING IMPROVED SEMICONDUCTOR-INSULATOR INTERFACE A method for passivating the surface of a compound semiconductor comprises annealing the substrate to form an anion rich surface layer containing cationic and anionic oxides and stripping the oxides to leave only a very thin anionic layer on the surface. The substrate is then subjected to an H2 plasma cleaning to remove chemisorbed oxygen. An N2 plasma cleaning is then performed to form an anionic nitride layer that is free of any cationic nitride. A layer of insulating material, such as, a native or other oxide, or a nitride, is deposited. The resulting structure has a very low interface state density such that the Fermi level may be swept through the entire band gap.
Abstract:
Metal silicide is removed at a faster rate than polysilicon in dry etching of metal silicide/polysilicon composites with an etching gas made from HCl and Cl2 at a volumetric flowrate ratio of HCl:Cl2 within the range of 3:1 to 5:1.
Abstract:
A process for forming the ridge structure of a self-aligned semiconductor laser, particularly useful for long wavelength devices as required for signal transmission systems. Described is the process as applied to an InP-system, double heterostructure (DH) laser. A thin Si3N4 layer (41) is inserted between the photoresist mask (42) that defines the ridge structure, and the contact layer (35). This results in improved adhesion and reduced etch undercutting whereby the ohmic contact area is increased, heat development decreased and device properties improved. Using a Si3N4 layer (41) deposited at a high plasma excitation frequency (RF) for adhesion promotion, and a low frequency deposited (LF) Si3N4 layer (43) for device embedding, provides for the etch selectivity required in the process step that is used to expose the contact layer to ohmic contact metallization deposition.