Additive for ALD deposition profile tuning in gap features

A method for performing atomic layer deposition (ALD) on a substrate, comprising:

• exposing the substrate to a first reactant and an additive, such that exposure to the first reactant and exposure to the additive are initiated substantially simultaneously, the first reactant and the additive being configured to adsorb on exposed surfaces of the substrate, a partial pressure of the first reactant and a partial pressure of the additive being configured so that adsorption of the additive in a gap feature of the substrate decreases as depth increases in the gap feature, wherein the first reactant is diisopropylaminosilane (DIPAS) or bis(diethylamine)silane (BDEAS), and wherein the additive is an alcohol or an organoamine,
• wherein, during the exposure to the first reactant and the additive that is initiated substantially simultaneously, the partial pressure of the additive is configured to prevent diffusion of the additive to a bottom of the gap feature and the partial pressure of the first reactant is configured to enable diffusion of the first reactant to the bottom of the gap feature,
• wherein exposing the substrate to the first reactant and the additive includes, pulsing the first reactant and the additive into a carrier gas stream that is flowed into a process chamber in which the substrate is disposed, wherein pulsing the first reactant and the additive into the carrier gas stream includes simultaneously turning on a flow of the first reactant and a flow of the additive into the carrier gas stream;
• performing a first purge operation;
• after exposing the substrate to the first reactant and the additive, exposing the substrate to a second reactant, the second reactant configured to react with the adsorbed first reactant to form a thin film product, the thin film product being silicon dioxide, the second reactant configured to react with the adsorbed additive to remove the adsorbed additive from the substrate surface,
• wherein exposing the substrate to the second reactant includes, pulsing the second reactant into the carrier gas stream;
• performing a second purge operation;
• repeating the operations of exposing the substrate to the first reactant and the additive substantially simultaneously, performing the first purge operation, exposing the substrate to the second reactant, and performing the second purge operation, for a predefined number of cycles so as to deposit multiple layers of the thin film product, wherein a deposition amount of the thin film product along sidewalls of the gap feature increases with increasing depth in the gap feature.