MOCVD Reactor Chamber Wall Temperature Control

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Solution Overview

Problem

Existing deposition devices face challenges in maintaining optimal temperature control between the susceptor and process chamber wall, particularly in HVPE and MOCVD processes, which affects layer quality and growth efficiency due to varying temperature gradients and parasitic growth issues.

Innovation Solution

The device allows for active heating and cooling of the process chamber wall using an RF heating coil, with adjustable temperature control within ±200° of the susceptor temperature, enabling precise temperature management through RF eddy currents and coolant channels, and the ability to switch between heating and cooling modes depending on the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the process chamber wall is actively heated to high temperature for HVPE process, then the layer deposition quality is improved, but parasitic growth on the chamber wall occurs

Engineering Contradiction:
Improvelayer deposition qualityVSAvoidparasitic growth
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The system divides the heating function into two independent zones: the susceptor (substrate holder) and the process chamber wall. Each can be heated or cooled independently through separate heating devices, allowing the substrate area to reach high temperatures for quality deposition while the chamber wall temperature is controlled to prevent parasitic growth

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different temperature conditions are applied to different locations within the process chamber. The susceptor and substrate area maintain high temperatures (up to 1000°C or more) for optimal layer deposition, while the process chamber wall temperature is independently controlled at lower levels to avoid parasitic growth, creating locally optimized thermal environments

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If the process chamber wall is actively cooled for MOCVD process, then parasitic growth is prevented, but layer deposition quality deteriorates

Engineering Contradiction:
Improveparasitic growth preventionVSAvoidlayer deposition quality
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The heating/cooling system is segmented into independent control zones for the susceptor and process chamber wall. During MOCVD process, the chamber wall can be actively cooled while the susceptor maintains optimal deposition temperature, preventing parasitic growth on walls while ensuring high-quality layer formation on substrates

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system creates different thermal conditions in different regions: the process chamber wall is cooled to prevent parasitic growth, while the susceptor and substrate area are maintained at high temperatures necessary for quality layer deposition, achieving locally optimized conditions for each function

Inventive Principle:
Principle #3Local quality

3Productivity

If the temperature gradient between susceptor and process chamber wall is increased, then deposition efficiency is improved, but temperature control precision deteriorates

Engineering Contradiction:
Improvedeposition efficiencyVSAvoidtemperature control precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts the temperature of both the susceptor and process chamber wall independently during the deposition process. Both heating devices can be controlled separately to optimize the temperature gradient for deposition efficiency while maintaining precise temperature control through independent regulation of each zone

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs temperature sensing and control mechanisms that monitor and adjust the temperatures of the susceptor and process chamber wall independently. This feedback control allows maintenance of optimal temperature gradients for efficient deposition while preventing excessive gradients that would compromise temperature control precision

Inventive Principle:
Principle #23Feedback

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

This solution enables flexible temperature control, preventing parasitic growth, optimizing layer deposition quality in both HVPE and MOCVD processes, and allowing for mixed process variants, thereby enhancing the efficiency and versatility of the deposition system.

Implementation Method 1

The process chamber wall opposite the susceptor is actively heated. Here, too, the energy is introduced via an RF field by means of an RF heating spiral into the process chamber ceiling made of conductive material

Methodology Applied
Scientific EffectRF eddy currents: Eddy Currents

Implementation Method 2

The process chamber wall opposite the susceptor is also actively heated. Here, too, the energy is introduced via an RF field by means of an RF heating spiral

Methodology Applied
Scientific EffectRF heating: Induction Heating

Implementation Method 3

the susceptor, which can be actively heated by a susceptor heating device

Methodology Applied
Scientific EffectSusceptor heating: Induction Heating

Implementation Method 4

the process chamber heating device having a coolant channel

Methodology Applied
Scientific EffectCoolant cooling: Cooling

Data Source

PatentEP2126161B1Device and method for selectively depositing crystalline layers using mocvd or hvpe
Publication Date: 2011.01.12 AIXTRON AG
  • EP2126161B1 patent drawingFigure 1
  • EP2126161B1 patent drawingFigure 2
  • EP2126161B1 patent drawingFigure 3

AI summary

The invention relates to a device for depositing one or more layers, in particular crystalline layers, on one or more substrates, in particular crystalline substrates (6), which are situated on a susceptor (3) in a process chamber (2) of a reactor (1). A process chamber wall (4) that can be actively heated by a process chamber heating unit (11) lies opposite the susceptor (3) that can be actively heated by the susceptor heating unit (11). The device is provided with a gas inlet organ (7) for introducing process gases into the process chamber and the process chamber heating unit (11) has a coolant channel (13) and is situated at a distance from the exterior (18) of the process chamber wall (4) during the active heating of the latter (4). The aim of the invention is to also allow the device to be used with hybrid technology. To achieve this, the process chamber wall (4) can be selectively actively heated and also actively cooled, the coolant channel (13) acting as a cooling unit (12) for the process chamber wall. The distance between the cooling unit (12) for the process chamber wall and said wall (4) can be altered from heating position that is at a distance to a cooling position by means of a displacement unit, which is in particular designed as a lifting unit.