Proton Radiation Donor Layer for Semiconductor On-Voltage Control
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Solution Overview
Problem
The increase in on-voltage and leakage current due to the formation of crystal defects by proton radiation in semiconductor devices, particularly in donor layers used for field stop and broad buffer structures, is not effectively addressed by existing methods, which also fail to specify the type of crystal defects formed and their impact on device performance.
Innovation Solution
The semiconductor device employs a method where proton radiation forms composite crystal defects involving vacancies, oxygen atoms, and hydrogen atoms, allowing for a high conversion rate of main crystal defects into donors without significantly increasing on-voltage or leakage current, by controlling the proton dose and heat treatment temperature within specific ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If proton radiation is used to form donor layers in drift layers, then the conversion rate of crystal defects into donors increases, but on-voltage and leakage current increase
Solution Approach 1:
The patent optimizes proton radiation parameters including dose (1×10^11 to 1×10^13 protons/cm²), acceleration energy (1 MeV to 10 MeV), and heat treatment temperature (300°C to 500°C) to control crystal defect formation and conversion, achieving high donor formation efficiency while suppressing on-voltage increase and leakage current
Solution Approach 2:
The patent creates composite crystal defects involving vacancies, oxygen atoms, and hydrogen atoms through proton radiation, forming VOH complexes that serve as effective donor sources while maintaining controlled electrical characteristics
2Reliability
If heat treatment is performed at high temperature to activate FS layer after ion implantation, then FS layer activation is achieved, but Al electrode film deteriorates
Solution Approach 1:
The patent performs proton radiation and heat treatment to form and activate the FS layer before forming the Al electrode film on the front surface, eliminating the need for subsequent high-temperature heat treatment that would damage the aluminum film
Solution Approach 2:
The patent reverses the conventional sequence by forming the FS layer through proton radiation and activating it at lower temperatures before aluminum electrode deposition, rather than implanting ions after aluminum film formation
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 effectively suppresses the increase in on-voltage and leakage current, maintaining device performance by optimizing the formation of donor layers through controlled proton radiation and heat treatment, specifically utilizing the VOH complex defect as a primary donor source.
Implementation Method 1
a composite crystal defect which is mainly caused by a vacancy, an oxygen atom, and a hydrogen atom is formed in the drift layer by proton radiation
Implementation Method 2
the composite crystal defect which is mainly caused by the vacancy, the oxygen atom, and the hydrogen atom is formed in the drift layer by proton radiation
Implementation Method 3
it is possible to effectively change a large number of main crystal defects into donors with a high rate
Implementation Method 4
changing a crystal defect formed in the drift layer by proton radiation into a donor
Implementation Method 5
a composite crystal defect which is mainly caused by the vacancy, the oxygen atom, and the hydrogen atom is formed in the drift layer by proton radiation
Data Source
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AI summary
A donor layer (3) which is formed by performing a heat treatment for a crystal defect formed by proton radiation is provided in an n-type drift layer (2) of an n- semiconductor substrate (1). The donor layer (3) has an impurity concentration distribution including a portion with the maximum impurity concentration and a portion with a concentration gradient in which the impurity concentration is reduce to the same impurity concentration as that of the n-type drift layer (2) in a direction from the portion with the maximum impurity concentration to both surfaces of the n-type drift layer (2). The crystal defect formed in the n-type drift layer (2) is a composite crystal defect mainly caused by a vacancy, oxygen, and hydrogen. The donor layer (3) provided in the n-type drift layer (2) makes it possible to suppress an increase in an on-voltage and an increase in a leakage current even when the density of crystal defects formed by the proton radiation is increased in order to increase the impurity concentration of the donor layer (3).