Intevac, Inc.

Gary A Davis

Verle W Aebi

John L Hughes

Carl T Petersen, Iii

Robert E Weiss

Robert J Kolenkow

Norman H Pond

Roger T Green

A magnetron sputtering source for depositing a material onto a substrate includes a target from which the material is sputtered, a magnet assembly disposed in proximity to the target for confining a plasma at the surface of the target and a drive assembly for scanning the magnet assembly relative to the target. The sputtering source may further include an anode for maintaining substantially constant plasma characteristics as the magnet assembly is scanned relative to the target. The anode may be implemented as variable voltage stationary electrodes positioned at or near the opposite ends of the scan path followed by the magnet assembly, spaced-apart anode wires positioned between the target and the substrate or a movable anode that is scanned with the magnet assembly. The magnet elements of the magnet assembly may have different spacings from the surface of the target to enhance depositional thickness uniformity. The target may be fabricated in sections, each having a target element bonded to a backing element for reduced sensitivity to thermal variations. The target may be rotated from a first fixed position to a second fixed position relative to the magnet assembly at least once during its operating life for increased target utilization.

Methods and apparatus for linear scan magnetron sputtering

A smooth and monotonic potential energy gradient was established at a p-type (InGa)As--undopad InP heterojunction to efficiently transfer conduction electrons from the (InGa)As:p layer to the InP:.o slashed. layer. This potential energy gradient was established with a compositionally graded p-type semiconductor alloy layer and an n-type InP built-in field layer interposed at the heterojunction. The compositionally graded semiconductor alloy layer spatially distributes the conduction band discontinuity of the (InGa)As--InP heterojunction and the InP:n built-in field layer eliminates potential energy barriers from the conduction band over a wide range of externally-applied biases including no externally applied bias. The smooth and monotonic potential energy gradient thus established promotes efficient transfer of the conduction electrons due to drift from the (InGa)As:p layer to the large bandgap InP collector layer where they contribute to the output current of any number of electronic devices. The utility of this potential energy grading structure was demonstrated in a transferred-electron photocathode device wherein the efficient transfer of photoelectrons from the (InGa)As:p absorber layer to the InP:.o slashed. electron-transfer layer has been utilized. This structure has utility in a number of electronic devices requiring such electron transfer across an (InGa)As:p--InP:.o slashed. heterojunction including p-i-n photodetectors and heterojunction bipolar transistors.

Heterojunction electron transfer device

High quality epitaxial layers can be grown on a multi-layer substrate which has a crystalline pseudomorphic layer with an exposed surface used for the epitaxial growth. The pseudomorphic layer of the substrate has a thickness at or below the pseudomorphic limit so it will be deformed as stress forces are developed during epitaxial growth of heteroepitaxial structures. A plastically deformable layer is bonded to the pseudomorphic layer, This plastically deformable layer is made of material that plastically flows at epitaxial growth temperatures.

Pseudomorphic substrates

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Fremont, CA, United States of America

Gary A Davis