Metal Silicate Layer Fabrication via Atomic Layer Deposition
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Solution Overview
Problem
Conventional methods for fabricating metal silicate layers, such as hafnium silicate, using atomic layer deposition face challenges in achieving precise thickness control and uniform composition ratios, leading to difficulties in forming successful and uniform layers due to chemically stable metal oxide layers formed during high cycle repetitions.
Innovation Solution
The method involves sequential steps of loading a substrate into a reactor, supplying metal and silicon source gases with alternating purging and oxidation steps, controlling the number of deposition cycles to form a metal silicate layer with a desired thickness and composition ratio, represented by the chemical formula MxSi1−xO2, where M is Hf, Zr, or Ti, and 'x' is controlled between 0.10 and 0.95.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of deposition cycles is increased to achieve desired thickness, then the thickness control is improved, but the formation of uniform metal silicate layer becomes difficult due to chemically stable metal oxide layers
Solution Approach 1:
The deposition process is segmented into distinct cycles, each consisting of metal source gas supply, purging, oxidation, and silicon source gas supply steps. This segmentation allows precise control of each stage to prevent formation of chemically stable metal oxide layers while achieving the desired thickness through controlled number of cycles.
Solution Approach 2:
Silicon source gas is supplied during the oxidation step when metal oxide layer is being formed, performing a preliminary action to prevent complete oxidation of the metal layer. This preliminary silicon introduction ensures uniform metal silicate layer formation even at high cycle repetitions.
2Device complexity
If conventional CVD or PVD techniques are used to fabricate metal silicate layer, then the process is simpler, but the step coverage and interface characteristics are poor
Solution Approach 1:
The ALD process uses periodic action with sequential supply of metal source gas, purging, oxidation, and silicon source gas in repeated cycles. This periodic action enables precise control of thin film formation, achieving excellent step coverage and interface characteristics that conventional CVD or PVD cannot achieve.
3Productivity
If high temperatures are used in CVD technique to form thin films, then the deposition rate is improved, but the thickness control precision deteriorates within tolerance of several Å
Solution Approach 1:
The process parameters including temperature, pressure, and gas flow rates are precisely controlled and optimized for each deposition cycle. By changing these parameters controllably through each cycle, the method achieves both high deposition rate and precise thickness control within atomic layer precision, overcoming the limitations of conventional CVD at high temperatures.
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 allows for precise control of the thickness and composition of metal silicate layers, overcoming the limitations of conventional techniques and enabling the formation of uniform layers with improved electrical properties.
Implementation Method 1
supplying a metal source gas into the reactor to form a chemical adsorption layer including the metal on the substrate
Implementation Method 2
supplying an oxide gas into the reactor to react with the chemical adsorption layer including the metal, thereby forming a metal oxide layer on the substrate
Implementation Method 3
supplying a silicon source gas into the reactor to form a chemical adsorption layer including silicon on the metal oxide layer
Implementation Method 4
supplying an oxide gas into the reactor to react with the metal oxide layer and the chemical adsorption layer deposited thereon, including the silicon, thereby forming a metal silicate layer
Data Source
AI summary
There are provided methods of fabricating a metal silicate layer on a semiconductor substrate using an atomic layer deposition technique. The methods include performing a metal silicate layer formation cycle at least one time in order to form a metal silicate layer having a desired thickness. The metal silicate layer formation cycle includes an operation of repeatedly performing a metal oxide layer formation cycle K times and an operation of repeatedly performing a silicon oxide layer formation cycle Q times. K and Q are integers ranging from 1 to 10 respectively. The metal oxide layer formation cycle includes the steps of supplying a metal source gas to a reactor containing the substrate, exhausting the metal source gas remaining in a reactor to clean the inside of the reactor, and then supplying an oxide gas into the reactor. The silicon oxide layer formation cycle includes supplying a silicon source gas, exhausting the silicon source gas remaining in the reactor to clean the inside of the reactor, and then supplying an oxide gas into the reactor.