International Business Machines Corporation

The United States of America as Represented by the Administrator of the

George E Alcorn

Geoffrey B Stephens

Raymond W Hamaker

James Downer Feeley

David L Bergeron

Charles Z Leinkram

John W Jackson, Jr

Julian Turner Lyman

Francis E Marshall

Olatunji Okunola

Andre S Burgess

Patrick A Grant

A process for fabricating an X-ray spectrometer having imaging and energy resolution of X-ray sources. The spectrometer has an array of adjoining rectangularly shaped detector cells formed in a silicon body. The walls of the cells are created by laser drilling holes completely through the silicon body and diffusing n.sup.+ phosphorous doping material therethrough. A thermally migrated aluminum electrode is formed centrally through each of the cells.

Method of fabricating an imaging X-ray spectrometer

A gallium arsenide photo-responsive device (40) is provided with an intermediate, transparent layer (28) of refractory metal or alkaline earth metal forming a tenacious bond between a non-hydroscopic oxide layer (24) and a noble metal Schottky barrier layer (30). The device has a gallium arsenide substrate with a predetermined type conductivity and a gallium arsenide epitaxial layer (16) with the same type conductivity but a lower charge carrier concentration grown on the substrate. The oxide layer (24) is formed to cover the epitaxial layer (16) and the transparent metal layer (28) followed by the noble metal layer (30) are deposited upon the oxide layer. An interdigitated ohmic contact (32) is then formed upon the noble metal layer.

GaAs Schottky barrier photo-responsive device and method of fabrication

An X-ray spectrometer for providing imaging and energy resolution of an X-ray source comprised of a thick silicon wafer (10) having an embedded matrix or grid of aluminum completely through the wafer fabricated, for example, by thermal migration. The aluminum matrix defines the walls (16, 18) of a rectangular array of silicon X-ray detector cells (14) or 'pixels'. A thermally diffused aluminum electrode (20) is also formed centrally through each of the silicon cells (14) with biasing means (22, 26, 28) being connected to the aluminum cell walls (16, 18) and the centralized aluminum electrode (20) for causing lateral charge carrier depletion between the cell walls so that incident X-ray energy causes a photo-electric reaction within the silicon producing collectible charge carriers in the form of electrons which are collected and used for imaging.

Imaging X-ray spectrometer

A double level metal interconnection structure and process for making same are disclosed, wherein an etch-stop layer is formed on the first metal layer to prevent over-etching thereof when forming the second level metal line in a via hole in an insulating layer thereover, by means of reactive plasma etching. The etch-stop layer is composed of chromium and the reactive plasma etching is carried out with a halocarbon gas.

Dense dry etched multi-level metallurgy with non-overlapped vias

An improved mask fabrication process is disclosed which may be broadly applied to ion-implantation, reactive plasma etching, or the etching of semiconductor structures. The process is based upon the deposition onto an oxide coated or bare semiconductor surface, of a first photoresist layer having formed therein a plurality of windows and which is hardened by a wet chemical technique so as to have an increased resistance to dissolution in solvents. A second photoresist layer is deposited over the surface and windows of the first layer and a subplurality of windows are formed therein over selected windows in the first photoresist layer so as to selectively block a portion of the plurality of windows in the first layer. This composite mask invention may then be employed to carry out an ion-implantation step, wet etching step or reactive plasma etching step on the oxide or semiconductor surface exposed through composite windows. The second layer of photoresist may then be removed and a substitute photoresist layer may be deposited on the surface and windows of the first, hardened photoresist layer and a different subplurality of windows in the substitute layer may be selectively formed over selected windows in the hardened photoresist layer, thereby selectively blocking a different combination of windows in the first, hardened layer.

Hardened photoresist master image mask process

Method for forming dense dry etched multi-level metallurgy with

A process is disclosed for forming a ledge-free aluminum-copper silicon conductor structure that is free of the silicon bridging problem which has produced electrical shorting conditions in the prior art. The process comprises the steps of depositing the aluminum-copper metallurgy, depositing a photoresist layer to delineate the shape of the resulting conductors, etching the aluminum copper metallurgy with phosphoric/nitric acid, for example, removing the photoresist, evaporating a layer of silicon on the surface of the etched conductor layer, sintering the composite to drive the necessary amount of silicon into the aluminum-copper, and removing the residual silicon layer by a reactive plasma etching technique. The resulting conductor structure is free of silicon bridging.

Process for forming a ledge-free aluminum-copper-silicon conductor

A process is disclosed for controlling the inclination of the side wall of a layer of sputtered quartz etched by a reactive plasma etching technique. The process consists of coating a selected fractional area of the backside of a silicon wafer to be etched, with a material resistant to plasma etching. Then coating the front side of the wafer bearing a layer of sputtered quartz, with a coating of organic material having a temperature dependent plasma etching rate, so as to delineate locations in the sputtered quartz layer for the formation of via holes. Next, exposing the wafer in a reactive plasma etching chamber. The inclination of the side wall of the via hole etched in the sputtered quartz layer by the reactive plasma etching step, may be controlled through the correlation of the selected area of exposure of the backside of the wafer, to the operating temperature under which the etching process proceeds which, in turn, governs the rate at which the organic layer is etched around the periphery of the via hole.

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Reston, VA, United States of America

George E Alcorn