Silicon-Phosphorous Vapor Deposition for Low-Temperature Uniform Doping
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Solution Overview
Problem
The microelectronic industry faces challenges in achieving uniform doping and high strain in silicon-containing materials at lower temperatures, with issues including reduced growth rate and dopant diffusion during deposition, especially in conformal dielectric films and high aspect ratio features.
Innovation Solution
A method for depositing silicon-phosphorous materials using silicon-phosphorous compounds in vapor deposition processes, including epitaxy and atomic layer deposition, at temperatures between 100°C and 700°C, with pressures ranging from 0.001 Torr to 600 Torr, to form films with high phosphorous concentration and low resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lower temperatures are used during deposition, then device performance is enhanced and ion implant damage is avoided, but growth rate and active dopant levels undesirably reduce
Solution Approach 1:
The patent changes the chemical composition parameters of the deposition gas by introducing silicon-phosphorous compounds with specific molecular structures (where x+y+z=3, representing the sum of silicon, phosphorous, and hydrogen atoms). This chemical parameter change enables phosphorous doping to occur at lower temperatures while maintaining adequate growth rates, as the silicon-phosphorous compound structure facilitates dopant incorporation without requiring high thermal energy.
Solution Approach 2:
The patent uses composite silicon-phosphorous compounds as the deposition gas material, combining silicon and phosphorous elements in specific molecular configurations. This composite material approach allows simultaneous achievement of low-temperature deposition (protecting device performance) and sufficient growth rate (maintaining productivity), as the compound structure enables both dopant delivery and film formation at reduced temperatures.
2Object-affected harmful factors
If lower temperatures are used during deposition, then ion implant damage is avoided, but active dopant levels and growth rate reduce
Solution Approach 1:
The patent modifies the deposition gas composition by using silicon-phosphorous compounds where the molecular structure (defined by x, y, z parameters summing to 3) enables efficient phosphorous delivery. This parameter change allows active dopant levels to be maintained at lower temperatures, avoiding ion implant damage while preventing the reduction in dopant effectiveness that normally occurs at reduced thermal energy.
3Manufacturing precision
If conventional doping methods are used, then dielectric materials can be doped, but doping profile control is difficult due to dopant diffusion during thermal process steps
Solution Approach 1:
The patent replaces the thermal field-based doping mechanism (which causes diffusion and poor profile control) with a chemical field-based mechanism using silicon-phosphorous compounds. By substituting the thermal process with a chemical vapor deposition process, the patent achieves precise dopant placement without the uncontrolled diffusion that occurs during thermal processing, thereby improving doping profile control and compositional stability.
Solution Approach 2:
The patent changes the process parameters from high-temperature thermal processing to lower-temperature chemical vapor deposition using silicon-phosphorous compounds. This parameter change reduces thermal energy input, thereby minimizing dopant diffusion while maintaining effective doping, leading to improved doping profile control and more stable dopant distribution in the deposited film.
4Area of stationary object
If conformal dielectric films are deposited on high aspect ratio features, then coverage is improved, but uniform doping becomes challenging
Solution Approach 1:
The patent changes the deposition parameters by using silicon-phosphorous compounds in a vapor deposition process at controlled temperatures and pressures. This parameter change enables the deposition gas to penetrate deep into high aspect ratio features while maintaining uniform phosphorous doping throughout the film, achieving both conformal coverage and doping uniformity that are difficult to obtain with conventional methods.
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 method enables fast growth rate, low deposition temperature, and reduced phosphorous diffusion, resulting in uniform doping and low resistivity silicon-phosphorous materials suitable for source and drain extensions without ion implant damage.
Implementation Method 1
exposing the substrate to a deposition gas containing one or more silicon-phosphorous compounds during a deposition process and depositing a film containing the silicon-phosphorous material on the substrate
Implementation Method 2
The substrate can be heated to a temperature of about 400° C. to about 700° C.
Data Source
AI summary
Embodiments generally relate to methods for depositing silicon-phosphorous materials, and more specifically, relate to using silicon-phosphorous compounds in vapor deposition processes (e.g., epitaxy, CVD, or ALD) to deposit silicon-phosphorous materials. In one or more embodiments, a method for forming a silicon-phosphorous material on a substrate is provided and includes exposing the substrate to a deposition gas containing one or more silicon-phosphorous compounds during a deposition process and depositing a film containing the silicon-phosphorous material on the substrate. The silicon-phosphorous compound has the chemical formula [(R3-vHvSi)—(R2-wHwSi)n]xPHyR′z, where each instance of R and each instance of R′ are independently an alkyl or a halogen, n is 0, 1, or 2; v is 0, 1, 2, or 3; w is 0, 1, or 2; x is 1, 2, or 3; y is 0, 1, or 2; z is 0, 1, or 2, and where x+y+z=3.