HfO2-ZrO2 Gate Insulator Crystallization at Low Temperature
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Solution Overview
Problem
High-temperature heat treatment of hafnium oxide (HfO2) films leads to crystallization and increased leak current due to grain boundary conduction, limiting the ability to achieve high relative permittivity and equivalent oxide thickness (EOT) reduction in semiconductor devices, especially under heat load constraints in transistor manufacturing processes.
Innovation Solution
A semiconductor device manufacturing method involving the formation of a gate insulating film with a mixture of hafnium oxide (HfO2) and zirconium oxide (ZrO2), subjected to a crystallization heat treatment at 600 degrees C or less, achieving a relative permittivity of 27 or more, and a substrate treatment system to control the film formation and heat treatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature heat treatment is applied to HfO2 film to increase relative permittivity, then the relative permittivity increases, but the HfO2 crystallizes and grain boundaries form causing increased leak current
Solution Approach 1:
The patent changes the chemical composition parameters of the insulating film by forming a mixed oxide film containing both HfO2 and ZrO2 in specific ratios (HfO2: 1-70 at%, ZrO2: 30-99 at%). This compositional parameter change allows the film to achieve high relative permittivity (k≥27) while maintaining amorphous structure at lower heat treatment temperatures (400-600°C), thereby preventing grain boundary formation and reducing leak current.
2Manufacturing precision
If heat treatment temperature is increased to reduce EOT, then the relative permittivity increases, but the process temperature range is limited by heat load constraints in transistor manufacturing
Solution Approach 1:
The patent changes the material composition parameter by using a mixed oxide system (HfO2-ZrO2) instead of pure HfO2. This allows the insulating film to achieve the required relative permittivity (k≥27) at lower heat treatment temperatures (400-600°C), thereby reducing EOT while staying within the heat load constraints of the transistor manufacturing process temperature range.
Solution Approach 2:
The patent employs a composite material approach by creating a mixed oxide film combining HfO2 and ZrO2 phases. This composite structure leverages the high permittivity of HfO2 while using ZrO2 to suppress crystallization and grain boundary formation, enabling effective heat treatment at moderate temperatures that are compatible with existing transistor manufacturing processes.
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 allows for the reduction of EOT and leak current over a wide temperature range, enabling the formation of high-permittivity insulating films suitable for processes with significant heat load constraints, while maintaining high relative permittivity and controlling leak current values.
Implementation Method 1
subjecting the insulation film to a crystallization heat treatment at a temperature of 600 degrees C. or less, the insulating film subjected to the crystallization heat treatment having a relative permittivity of 27 or more
Data Source
AI summary
A semiconductor device manufacturing method that includes: forming a gate insulating film containing a hafnium oxide and a zirconium oxide on a workpiece having a source, a drain and a channel; and subjecting the gate insulating film to a crystallization heat treatment at a temperature of 600 degrees C. or less is provided. The gate insulating film subjected to the crystallization heat treatment has a relative permittivity of 27 or more.