International Business Machines Corporation

Francis Rodier

Patrick Raffin

Jean-Marc Rousseau

Caroline Aussilhou

Corinne Buchet

Rajarao Jammy

Heidi L Greer

Susan E Chaloux

Mathias Bostelmann

Corine Bucher

Jean-Pierre Mazur

Olivier Beyaert

The present invention relates generally to an improved ladder boat for supporting semiconductor wafers during thermal treatments which comprises top and bottom plates vertically opposing each other and support rods secured to said plates. Said support rods are provided with dividers for supporting a plurality of wafers one above another in a parallel arrangement. The dividers have a special profile to include a ramp portion so that the wafer is seated at a sharp corner thereof. Therefore, the contact surface between the wafer backside at its periphery and the dividers is segmental or punctual. This contact is preferably performed outside the contact area between the wafer backside and the wafer support zones of the electrostatic chuck of the photolithography tool to be subsequently used in the course of the wafer manufacturing.

Ladder boat for supporting wafers

There is disclosed a method of forming a buried strap (BS) and its quantum conducting barrier (QCB) in a structure wherein a doped polycrystalline silicon region is exposed at the bottom of a recess and separated from a monocrystalline region of a silicon substrate by a region of an insulating material. First, a thin continuous layer of undoped amorphous silicon is deposited by LPCVD to coat said regions. The surface of this layer is nitridized to produce a Si N QCB film. Now, at least one dual layer comprised of an undoped amorphous silicon layer and a dopant monolayer is deposited onto the structure by LPCVD. The recess is filled with undoped amorphous silicon to terminate the buried strap and its QCB. Finally, the structure is heated to activate the dopants in the buried strap to allow an electrical continuity between said polycrystalline and monocrystalline regions through the QCB by a quantum mechanical effect. All these steps are performed in situ in the same LPCVD tool.

Methods of forming the buried strap and its quantum barrier in deep trench cell capacitors

A multilayered quantum conducting barrier (MQCB) structure formed on two semiconductor regions having a different crystalline nature and a thin layer of an insulating material sandwiched between said semiconductor regions. An undoped amorphous silicon layer continuously coats these two semiconductor regions and insulating layer. The surface of the undoped amorphous silicon layer is nitridized to produce a superficial film of a nitride based material to form the desired quantum conducting barrier (QCB). A stack consisting of at least one dual layer comprised of a bottom undoped amorphous silicon layer and a top dopant monolayer is formed on said undoped amorphous silicon layer. After thermal processing, the MQCB structure operates as a strap allowing an electrical continuity between these semiconductor regions through the QCB by a quantum mechanical effect.

Multilayered quantum conducting barrier structures

Improved reliability structures containing quantum conductive barrier layer structures are obtained by employing quantum conductive layers in combination with thin regions of amorphous or microcrystalline semiconductor material. The quantum conductive structures are especially useful when incorporated into trench capacitors to reduce or eliminate the occurrence of low temperature fails and single cell fails in DRAM circuits.

Structures containing quantum conductive barrier layers

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Mondeville, France

Francis Rodier