In-Chamber Microplasma ALD Reactor for Low-Temperature Precursor Dissociation
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Solution Overview
Problem
Conventional atomic layer deposition (ALD) and plasma-enhanced ALD (PEALD) processes face challenges such as layer intermixing due to atomic diffusion on heated substrates, incomplete monolayer growth, and inefficiencies in precursor dissociation, which are exacerbated by the need for complex and costly external plasma sources.
Innovation Solution
Incorporating an in-chamber plasma source with microcavity or microchannel arrays within the deposition reactor, allowing for plasma-enhanced ALD at high pressures and efficient precursor dissociation, reducing substrate temperature, and ensuring complete monolayer growth in each cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If substrate temperature is increased to promote precursor dissociation in conventional ALD, then precursor dissociation efficiency is improved, but atomic diffusion increases causing layer intermixing
Solution Approach 1:
The patent replaces thermal energy (heating) with plasma energy for precursor dissociation. The plasma source generates reactive species that dissociate precursors at lower substrate temperatures, eliminating the need for high-temperature heating that causes atomic diffusion and layer intermixing.
Solution Approach 2:
The patent changes the energy delivery mechanism from thermal to plasma-based. By introducing plasma as the energy source, the system achieves effective precursor dissociation at lower temperatures, fundamentally altering the process parameters to avoid the harmful effects of thermal heating.
2Use of energy by moving object
If external plasma sources are used for PEALD, then precursor dissociation is enhanced, but device complexity and cost increase
Solution Approach 1:
The patent merges the plasma generation function directly into the deposition chamber by integrating a plasma source within the reaction chamber. This eliminates the need for separate external plasma sources and their associated complex impedance-matching electronics and antennas, simplifying the overall system while maintaining effective precursor dissociation.
Solution Approach 2:
The integrated plasma source performs multiple functions within a single component: it generates plasma for precursor dissociation, provides reactive species for film growth, and operates within the deposition chamber without requiring separate external systems. This multi-functionality reduces device complexity and cost.
3Manufacturing precision
If conventional ALD sequential process is used, then film conformality is achieved, but deposition rate is limited to one monolayer per cycle
Solution Approach 1:
The patent enables continuous film growth by using plasma to dissociate precursors and provide reactive species that allow multiple atomic layers to form in a single deposition cycle rather than requiring sequential monolayer-by-monolayer growth. This continuous action maintains conformality while dramatically increasing deposition rate.
Solution Approach 2:
The patent changes the deposition mechanism from sequential monolayer growth to continuous multi-layer growth by introducing plasma. The plasma-generated reactive species enable rapid reaction and film formation that maintains the self-limiting conformal deposition characteristic while achieving much higher growth rates.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The in-chamber plasma source enables rapid, efficient, and uniform deposition of high-quality ultrathin films with reduced impurities, achieving growth rates close to the theoretical maximum and maintaining film conformality, even on complex substrate structures.
Implementation Method 1
it was recognized that plasmas could be useful in partially 'cracking' precursors. Known as plasma-enhanced atomic layer deposition (PEALD), this process involves the installation of a plasma device or system outside the deposition tool. Partial or complete dissociation of precursors with a plasma
Implementation Method 2
The energy required to dismantle (dissociate) the precursors and 'liberate' the desired atom(s) is supplied by temperature. That is, the substrate on which a film is to be grown is heated so as to promote the dissociation of the precursor at the hot surface
Implementation Method 3
Heating of the substrate also increases atom mobility that is generally desirable for the formation of crystalline films. The drawback of this approach is that state-of-the art electronic devices are multi-layered, and the growth of a thin film onto a stack of already-deposited films on a heated substrate has the unintended consequence of causing the layers to partially intermix because of atomic diffusion
Implementation Method 4
Atomic layer deposition (ALD) is the preferred process for depositing thin films with atomic precision. First demonstrated in 1974 by Dr. Tuomo Suntola of the University of Helsinki for electroluminescent displays, ALD is a sequential deposition process in which one layer of atoms is deposited at a time
Data Source
AI summary
An in-chamber plasma source in a deposition reactor system includes an array of microcavity or microchannel plasma devices having a first electrode and a second electrode isolated from plasma in microcavities or microchannels. An inlet provides connection to deposition precursor. A region interacts deposition precursor with plasma. An outlet directs precursor dissociated with the plasma onto a substrate for deposition. A reactor system includes a substrate holder across from the outlet, a chamber enclosing the in-chamber plasma source and the substrate holder, an exhaust from the chamber, and conduit supplying precursors from sources or bubblers to the inlet. A reactor system can conduct plasma enhanced atomic layer deposition at high pressures and is capable of forming a complete layer in a single cycle.