Bell Communications Research, Inc.

Exxon Research and Engineering Company

Eli Yablonovitch

Thomas J Gmitter

Harry William Deckman

Horst Witzke

Brian G Bagley

Christopher R Wronski

Claude J Sandroff

Bernard R Weinberger

In the fabrication of microelectronic, optoelectronic, and photonic devices, methods are being used which involve selective processing of material in the presence of a patterned mask layer; for example, such processing may involve etching. Typically, mask layer material is chosen on the basis of response to suitable radiation, allowing for patterning by selective irradiation followed by selective removal of mask layer material. However, in so-called epitaxial lift-off processing, material to be processed may be covered with a support layer of a material which is selected in view of desired mechanical and thermal properties, and which is not amenable to patterning by radiation. A method is described which provides for patterning of such layer by heated mechanical means such as a heated stylus or roller.

Patterning method for epitaxial lift-off processing

An omnidirectional optical reflector structure (41, 52, 61) is made by forming a plurality of holes in a solid body (11) so as to result in a face-centered cubic lattice. Conventiently, the desired structure can be made by three successive steps of microfabrication, e.g., in the presence of a mask layer (12). Preferred reflector structures can be used, e.g., as external mirrors as filters, and as cavity materials of communications lasers with improved signal-to-noise ratio.

Optical reflector structure, device, method of fabrication, and

A method of passivating GaAs and InGaAs by growing on the GaAs or InGaAs used for semiconducting devices a surface film of glassy As.sub.2 S.sub.3 which acts as a passivating layer. The film growth is preferably done by precipitating As.sub.2 S.sub.3 from a solution containing NH.sub.4 OH, so as to make it basic, and then annealing the precipitated film at a temperature between the glass transition temperature (200.degree. C.) and the melting point (315.degree. C.) of As.sub.2 S.sub.3.

Arsenic sulfide surface passivation of III-V semiconductors

A method for removing an epitaxial film from a single crystal substrate upon which it is grown and adhering the films to second substrate and the resultant structure. The removing method comprises (a) providing a thin release layer (.ltoreq.100 nm) between the film to be grown and the single crystal substrate; (b) growing the epitaxial film; (c) applying a polymeric support layer which is under tension over the film; and (d) selectively etching the release layer, the tension in the support layer causing the edges of the film to curve upwardly as the release layer is etched away. The adhering method uses either adhesives or relies solely on Van der Waals bonding between the epitaxial film and the second substrate.

Lift-off and subsequent bonding of epitaxial films

A method for removing epitaxial films from a single crystal substrate upon which it is grown comprising (a) providing a thin release layer (.ltoreq.1000A) between the film to be grown and the substrate; (b) growing the epitaxial film(s); (c) applying a polymeric support layer which is under tension over the film; and (d) selectively etching the release layer, the tension in the support layer causing the edges of the film to curve upwardly as the release layer is etched away.

Method for lifting-off epitaxial films

A method of passivating the surface of an indium gallium arsenide substrate by cleaning the indium gallium arsenide substrate in an etching solution and depositing a sodium hydroxide film on the substrate. The step of depositing the sodium hydroxide film is preferably performed by spin-on of a sodium hydroxide solution, followed by drying or annealing. The resulting passivated surface exhibits superior surface recombination velocity characteristics compared to prior art passivation techniques, thereby making possible superior solid state device operating characteristics.

Passivation of indium gallium arsenide surfaces

A method of making a semiconductor laser from a gallium arsenide substrate of a first conductivity type by depositing a first layer of semiconductor material having the composition Al.sub.x Ga.sub.1-x As of first conductivity type on the substrate and a thin second layer of semiconductor material for quantum confinement having the composition In.sub.y Ga.sub.1-y As on the first layer. This layer experiences sufficient strain in the semiconductor structure so as to minimize the threshold current density. The device is completed by depositing a third layer of semiconductor material having the composition Al.sub.x Ga.sub.1-x As and of second conductivity type on the second layer, and depositing a fourth layer of semiconductor material having the composition GaAs and of second conductivity type on the third layer.

Method of making a DH laser with strained layers by MBE

A method of passivating the surface of a gallium arsenide substrate by cleaning the gallium arsenide substrate in an etching solution and depositing a sulfide film on the substrate. The step of depositing the sulfide film is preferably performed by spin-on of a sodium sulfide solution, followed by drying or annealing. The resulting passivated surface exhibits superior surface recombination velocity characteristics compared to prior art passivation techniques, thereby making possible superior solid state device operating characteristics.

Passivation of gallium arsenide surfaces with sodium sulfide

A method is described for producing an electronically passivated stable surface on silicon wafers. The passivation technique consists of first fluorinating the surface of a crystalline silicon wafer under inert atmospheric conditions. Such a treatment may consist of either a vapor phase or liquid phase application of HF at room temperature. The surface fluorinated wafer is then maintained in an inert atmosphere and a thin coating of an organic solid is applied to the wafer which does not disturb the underlying passivated silicon surface. The wafer may then be further processed into a variety of different devices.

Method for producing an electronically passivated surface on crystalline

The present invention is a method for producing an optically enhanced thin film photovoltaic device. The method includes the steps of producing an active layer of semiconductor material wherein the surface of at least one side of the active layer is textured such that the surface includes randomly spaced, densely packed microstructures of predetermined dimensions of the order of the wavelength of visible light in the semiconductor material and attaching a reflecting surface directly to one side of the semiconductor material and making an ohmic contact to the material.

Method for making optically enhanced thin film photovoltaic device using

An ultra-high efficiency inverted solar cell structure is disclosed. At the rear of the cell is a high performance heterocontact made of SIPOS (a mixture of micro-crystalline silicon and silicon dioxide). At the edge of the cell, the opposite contact is of conventional heavily doped silicon. The edge contact is kept in the dark at least one diffusion length or one-third mm laterally displaced away from both the active illuminated region and from the active heterocontact.

Growing community of inventors

Scotch Plains, NJ, United States of America

Eli Yablonovitch