US 5,332,689 A · Method for depositing low bulk resistivity doped films

Abstract

An LPCVD deposition process for depositing doped thin films on a substrate is provided. The process may be performed in a LPCVD reaction chamber at elevated temperatures and reduced pressures. The process is especially suited to the deposition and doping of chemically incompatible deposition species and dopants such as polysilicon and arsenic. A deposition gas (e.g. silane) and a dopant gas (e.g. arsine) are thermally decomposed in the reaction chamber. During the deposition process the gas flows are pulsed relative to one another in some manner. This pulsed gas flows form a multi-layer stack which includes alternating deposition layers and doping layers. The dopants in the doping layer are then diffused during a subsequent annealing step (or during subsequent processing) into the deposition layers to form a uniformly doped thin film.

Claims10

Dependent claims

In semiconductor manufacture an LPCVD method for forming an arsenic doped polysilicon thin film having a low bulk resistivity on a substrate, comprising:

placing the substrate in a LPCVD reaction chamber;
maintaining the substrate and the reaction chamber under a vacuum pressure;
introducing and thermally decomposing a silicon deposition gas in the reaction chamber for depositing a polysilicon deposition film layer on the substrate;
introducing and thermally decomposing an arsenic dopant gas in the reaction chamber for depositing an arsenic film layer on the substrate;
pulsing the silicon deposition gas flow and the arsenic dopant gas flow by switching the silicon deposition gas and the arsenic dopant gas on and off in opposite phase so that arsenic will not poison the deposition of the polysilicon film layer such that a multi-layer stack is formed including single species polysilicon film layers and single species arsenic film layers;
and
diffusing arsenic dopants from the arsenic film layers into the polysilicon film layers such that a uniformly doped film layer is formed.

4 more elements

Dependencies are inferred from the claim text.

Method for depositing low bulk resistivity doped films

Life of this patent

Method for depositing low bulk resistivity doped films

Life of this patent

Abstract

Claims10