Semiconductor Doping via Proton and Electron Irradiation
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Solution Overview
Problem
Proton irradiation for n-type doping in semiconductors, particularly silicon, results in a doping concentration maximum that is not thermally stable and limited in depth, with further increases in proton dose leading to reduced efficiency and non-uniform distribution due to excess hydrogen atoms.
Innovation Solution
Combining proton irradiation with electron irradiation followed by heat treatment to create additional vacancies for hydrogen attachment, allowing for increased and uniform doping concentrations by adjusting the ratio of hydrogen atoms to vacancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the proton dose is increased to achieve higher doping concentrations, then the doping concentration increases, but the distribution becomes non-uniform and efficiency decreases due to excess hydrogen atoms
Solution Approach 1:
The patent introduces electron irradiation as an intermediary process that creates vacancies which serve as binding sites for hydrogen atoms. This mediator (vacancies created by electrons) enables the excess hydrogen atoms from proton irradiation to be properly bound and distributed, transforming the harmful excess hydrogen into useful doping agents and achieving uniform doping distributions at concentrations up to 10^15 cm^-3
2Quantity of substance
If proton irradiation is used for n-type doping, then doping is achieved, but a doping concentration maximum forms that is not thermally stable
Solution Approach 1:
The patent applies electron irradiation before heat treatment to pre-create vacancies throughout the semiconductor bulk. These pre-created vacancies are then available during subsequent heat treatment to bind hydrogen atoms uniformly, preventing the formation of unstable concentration maxima and ensuring thermally stable doping distributions
3Length of stationary object
If proton irradiation is used for deep doping, then doping depth increases, but doping efficiency decreases due to limited vacancy availability
Solution Approach 1:
The patent uses electron irradiation to create vacancies that serve a universal function throughout the entire semiconductor bulk, regardless of depth. These vacancies enable efficient hydrogen binding at all depths, allowing deep doping to be achieved with maintained or improved efficiency compared to shallow regions
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 significantly enhances doping efficiency and achieves more uniform doping distributions across the semiconductor, with doping concentrations up to 1015 cm^-3, while allowing for the removal of the doping maximum by thinning the semiconductor if necessary.
Implementation Method 1
irradiating the semiconductor body with protons
Implementation Method 2
the heat treatment results in diffusion of the hydrogen atoms produced from the protons radiated
Implementation Method 3
irradiating the semiconductor body with electrons. After the process of irradiating with protons and after the process of irradiating with electrons, the semiconductor body is subjected to heat treatment
Implementation Method 4
the semiconductor body is subjected to heat treatment. The heat treatment results in diffusion of the hydrogen atoms produced from the protons radiated
Implementation Method 5
The heat treatment results in diffusion of the hydrogen atoms produced from the protons radiated in order that said hydrogen atoms are attached to vacancies
Data Source
AI summary
A description is given of a method for doping a semiconductor body, and a semiconductor body produced by such a method. The method comprises irradiating the semiconductor body with protons and irradiating the semiconductor body with electrons. After the process of irradiating with protons and after the process of irradiating with electrons, the semiconductor body is subjected to heat treatment in order to attach the protons to vacancies by means of diffusion.