Temperature Controlled Layer for MOCVD Substrate Uniformity
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Solution Overview
Problem
In MOCVD growth processes, achieving uniform temperature distribution over a wafer substrate is challenging due to non-uniform heating from conventional heating sources, leading to variations in semiconductor layer composition and deposition rates, which can result in damaged or non-uniform epitaxially grown layers.
Innovation Solution
Implementing a temperature-controlled layer on the substrate or susceptor with a metallic domain, such as Molybdenum or Tungsten, with a continuous thickness profile or specific shapes like concave surfaces and nanochannels, to optimize heating uniformity and prevent temperature jumps, coupled with a control unit and in-situ measurement system to adjust heating radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heating sources (inductive heating coils, resistive heating coils, or lamps) are used to heat the wafer substrate, then the wafer substrate can be heated to a predetermined temperature set point, but the temperature distribution imparted onto the wafer substrate becomes non-uniform
Solution Approach 1:
The patent applies local quality by creating a non-uniform thickness profile of the susceptor, where the susceptor is thinner at the center and thicker at the edges. This varying thickness provides different thermal conductivities at different locations, allowing the center and edge regions to reach different temperatures during heating. The non-uniform susceptor structure compensates for the non-uniform temperature distribution caused by conventional heating sources, achieving uniform temperature across the wafer substrate surface.
2Reliability
If the wafer substrate is placed directly on a rotating susceptor for support during epitaxial growth, then the susceptor provides mechanical support and protects the back side of the wafer, but precise control of temperature distribution becomes difficult
Solution Approach 1:
The patent applies parameter changes by modifying the physical parameters of the susceptor, specifically its thickness distribution. The susceptor is designed with a continuous non-uniform thickness profile that varies radially from center to edge. This geometric parameter change allows the susceptor to function both as a mechanical support structure and as a thermal management device that actively controls temperature distribution across the wafer substrate during epitaxial growth.
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 approach enhances temperature uniformity, reducing operation and process variations, improving the quality and yield of epitaxially grown semiconductor layers by maintaining precise control over the growth process parameters.
Implementation Method 1
The metallic domain can be placed over a central area of the substrate or the susceptor... selecting an electrically conducting metal having a high melting temperature that optimizes a temperature uniformity over the substrate
Implementation Method 2
a heating unit configured to heat the wafer substrate on the susceptor... generate a heating radiation that imparts a uniform temperature distribution over the substrate
Implementation Method 3
a MOCVD growth process in which semiconductor layers are epitaxially grown on the substrate... Metal-Organic Chemical Vapor Deposition (MOCVD) growth process
Data Source
AI summary
A metal-organic chemical vapor deposition (MOCVD) growth with temperature controlled layer is described. A substrate or susceptor can have a temperature controlled layer formed thereon to adjust the temperature uniformity of a MOCVD growth process used to epitaxially grow semiconductor layers. In one embodiment, the substrate and/or the susceptor can be profiled with a shape that improves temperature uniformity during the MOCVD growth process. The profiled shape can be formed with material that provides a desired temperature distribution to the substrate that is in accordance with a predetermined temperature profile for the substrate for a particular MOCVD process.