Rainmaker Humidification System

Droplet-Free Water Vapor for ALD and Oxidation

The RainMaker Humidification System (RHS) is a precisely controlled oxide source for droplet-free deposition.

The RainMaker Humidification System (RHS) Enables Semiconductor Applications


VCSELs (Vertical-Cavity Surface-Emitting Laser) are used in a growing number of devices. These structures require precise oxidation of the aperture to form the laser channel. Aperture oxidation is controlled via process temperature, composition of the aperture structure, and water vapor delivered into the process chamber. The RHS delivers precisely controlled, ultrapure water vapor.

Precision Thermal Oxidation

Precision water-vapor delivery is difficult with standard market products. Bubblers and Flash Vaporizers are particle generators, and will hit wafers with microdroplets. This causes non-uniform oxidation and island growth on the wafer surface.

High Performance Thermal Oxides

High performance oxides require high density, high refractive index and excellent dielectric properties. Ultra-high purity water vapor is needed. Ionic contamination, organic contamination, particles, and dissolved gases are typical in traditional water-vapor delivery products. These impurities can interfere with high performance processes, leading to poor electrical characteristics, non-uniformity and other defects.

RHS Beats Traditional Delivery Methods

High Concentration

The Peroxidizer delivers 10x concentration of hydrogen peroxide gas at a given temperature and delivers droplet-free gas at temperatures as low as 80 °C. The Peroxidizer delivers up to 5% hydrogen peroxide gas by volume from 30% hydrogen peroxide liquid solution.

Bigger Precursor Range

New materials and architectures are more temperature sensitive than their predecessors, such as SiGe and new memory alloys, forcing lower thermal budgets. Hydrogen peroxide gas from the Peroxidizer has higher reactivity at lower temperature, increasing the range of precursors available to process engineers.

Strong Oxidant

Hydrogen peroxide gas readily converts to highly reactive OH radicals , creating a high density ALD nucleation and faster reactions with precursors. Oxygen plasma can penetrate below the interface layer, damaging the bottom electrode and surface structures. Plasma cannot reach the bottom of deep structures as it requires line-of-sight, so coatings may be non-uniform, favoring the top of the structure.

Low Temperature 

High concentration hydrogen peroxide gas delivered by the Peroxidizer creates a dense hydroxylated layer at a lower operating temperature than other oxidants. To achieve the same level of reactivity, water requires higher process temperatures that are not compatible with new materials.

Get Particle Testing Results

How the RHS Works

The RHS adds controlled amounts of pure water vapor directly into any carrier gas stream. Needing only filtered house de-ionized (DI) water and power, the system delivers precise amounts of water vapor into atmospheric processes.

The RHS is an integrated water vapor delivery system featuring adaptive closed loop control. Process parameters are set through automated process recipes or the controller touchscreen. Internal pressure, flow and temperature sensors provide feedback to the control system, which automatically adjusts operations to maintain required temperature and concentration stability.

The RHS consists of a non-porous membrane that excludes particles, micro-droplets, volatile gases, and other opposite charged species from being transferred to the carrier gas and ensures only water vapor is added. The membrane selects only the source gas molecules. Other contaminants in the liquid source cannot permeate across the membrane or enter the carrier gas stream, resulting in a saturated product that is consistent and pure. 

See Latest Research on Oxides.

Latest News

Record Low Resistivity Titanium Nitride Film Fabricated by Thermal ALD – Ultra-dry hydrazine enables growth at low temperature


Low resistivity is an indicator of a high-quality film that works well as a barrier layer or conductor. TiN thin films are used as diffusion barriers for cobalt (Co) and tungsten (W) metal layers as well as gate metal in CMOS devices due to their high electrical
conductivity and related low resistivity.


The Emergence of Hydrazine (N2H4) in Semiconductor Applications


Historically, metal-nitride MOCVD and ALD ALD films have used Ammonia (NH3) for fabrication of advanced semiconductor devices. However, lower thermal budgets and shrinking 3-dimensional structures needed in next generation devices have exposed limitations with ammonia usage in semiconductor processing. However, these studies are far from comprehensive due to the vast number of possible metal nitrides along with a countless number of potentially useful metal precursor materials.


Technical White Paper – ALD Nitride Wizard


In recent years production worthy, ultra-dry gas-phase Brute© hydrazine (N2H4) has been developed and made available by Rasirc. Prior to this work, attempts to deliver hydrazine gas were technically challenged due to moisture and safety issues which caused many studies to produce inconsistent results with oxygen incorporation into films.1-3 Therefore, little was actually known about low moisture gas phase N2H4reactivity in ALD and other potential nitridation applications.


RainMaker Humidification System (RHS) Datasheet


The RHS purifies and precisely controls water vapor delivery, reducing costs, increasing yield and improving throughput. Delivery of water vapor can be controlled from low ppm levels to high concentrations.


RainMaker Humidification System for Precise Delivery of Water Vapor into Atmospheric and Vacuum Applications


Water vapor has multiple applications across industries including semiconductor, photovoltaic, fuel cells, carbon nanotubes, glass coating, and pharmaceuticals. Precise control of this water vapor is necessary to ensure that product yield and performance are consistent. In many of these applications, the process is performed in a vacuum.


Particle Generation by Incomplete Vaporization of Condensable Fluids and Particle Prevention by Membrane Pervaporation


A study was conducted to compare the relative particle/microdroplet generation of pervaporation versus a flash vaporizer in both continuous and intermittent flow conditions. This paper details that study and includes particle data when applied to ALD film growth in the appendix.


RASIRC products generate and deliver water vapor, hydrogen peroxide and hydrazine gas in controlled, repeatable concentrations to critical processes.



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