Semiconductor Impurity Reduction via Particle Irradiation and Thermal Out-Diffusion
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Solution Overview
Problem
In semiconductor devices, such as IGBTs and IGFETs, low doping concentration is achieved through base material doping, but additional impurities from growth processes like magnetic Czochralski growth can form undesired complexes, altering doping concentrations and recombination/generation characteristics, necessitating a method to reduce impurity concentrations.
Innovation Solution
Irradiating the semiconductor body with particles, followed by thermal treatment between 450°C to 1200°C, to remove impurities through out-diffusion, thereby reducing nitrogen and carbon concentrations and avoiding complex formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low doping concentration is used in base material, then DC voltage blocking requirement is achieved, but additional impurities from growth processes form undesired complexes altering doping concentration and recombination/generation characteristics
Solution Approach 1:
The patent applies preliminary action by performing particle irradiation and thermal treatment on the base material before FEOL processing. This pre-treatment reduces impurity concentrations and prevents the formation of undesired complexes during subsequent processing steps, thereby maintaining reliable doping concentrations and recombination/generation characteristics throughout device operation
Solution Approach 2:
The patent converts the harmful effect of impurities into a benefit by using particle irradiation to activate impurity out-diffusion. The thermal treatment process transforms the stationary harmful impurities into mobile species that can be removed from the base material, turning the impurity problem into a controlled removal process that improves overall device reliability
2Ease of manufacture
If additional impurities are present from growth process, then base material can be produced, but undesired complexes including electrically active complexes alter doping concentration and recombination/generation characteristic
Solution Approach 1:
The patent performs particle irradiation and thermal treatment as a preliminary step before FEOL processing to reduce impurity concentrations in the base material. This pre-treatment ensures that subsequent doping and processing steps achieve precise doping concentration control without interference from unwanted impurity complexes
Solution Approach 2:
The patent changes physical parameters by applying particle irradiation (changing the energy state of impurities) and thermal treatment (changing temperature from ambient to 450-1200°C). These parameter changes activate impurity mobility and enable selective removal, thereby improving manufacturing precision of doping concentrations
3Ease of manufacture
If additional impurities are present from growth process, then base material can be produced, but recombination/generation characteristic is altered
Solution Approach 1:
The patent applies particle irradiation and thermal treatment before FEOL processing to remove impurities that would otherwise alter recombination/generation characteristics. This preliminary purification ensures that the base material maintains reliable recombination/generation characteristics throughout device operation
Solution Approach 2:
The patent converts the harmful presence of impurities into a beneficial removal process. By using particle irradiation to activate impurity mobility followed by thermal treatment, the patent enables selective out-diffusion and removal of impurities, thereby improving recombination/generation characteristics while maintaining ease of base material production
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 method effectively reduces impurity concentrations, enhancing the reliability of doping profiles and recombination/generation characteristics in semiconductor devices, improving their performance and manufacturing consistency.
Implementation Method 1
removing at least a part of impurities from an irradiated part of the semiconductor body by out-diffusion during thermal treatment in a temperature range between 450° C. to 1200° C.
Implementation Method 2
thermal treatment in a temperature range between 450° C. to 1200° C.
Data Source
AI summary
A method of manufacturing a semiconductor device includes irradiating the semiconductor body with particles through a first side of the semiconductor body, removing at least a part of impurities from an irradiated part of the semiconductor body by out-diffusion during thermal treatment in a temperature range between 450° C. to 1200° C., and forming a first load terminal structure at the first side of the semiconductor body.