Semiconductor Device Back-Surface Proton Injection
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Solution Overview
Problem
Conventional methods for repairing crystal defects in semiconductor substrates using proton injection and thermal processing are inefficient due to the shielding effect of barrier metals, leading to increased manufacturing costs from multiple thermal processes.
Innovation Solution
A semiconductor device and manufacturing method involving an n-type impurity region with varying carrier concentrations, where protons are injected from the back surface to spread and repair defects, including those at the boundary between the gate insulating film and the semiconductor substrate, reducing the need for multiple thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protons are injected through the barrier metal layer to repair defects, then defect repair is achieved, but the barrier metal shields protons and prevents sufficient defect repair
Solution Approach 1:
Instead of injecting protons from the front surface through the barrier metal layer, the patent inverts the approach by injecting protons from the back surface of the semiconductor substrate. This allows protons to reach the defect regions without being blocked by the barrier metal layer, effectively resolving the shielding problem while achieving comprehensive defect repair.
Solution Approach 2:
The patent changes the injection dimension by transitioning from front-surface injection (through the barrier metal) to back-surface injection. This dimensional change allows protons to approach defects from a different direction, bypassing the shielding effect of the barrier metal layer and enabling effective defect repair in regions that would otherwise be inaccessible.
2Reliability
If multiple thermal processing steps are performed after proton injection to repair defects, then defect repair is improved, but manufacturing cost increases
Solution Approach 1:
The patent performs preliminary defect repair by injecting protons from the back surface before subsequent processing steps. This preliminary action creates a favorable initial state that reduces the need for multiple corrective thermal processing steps, thereby lowering manufacturing costs while maintaining high defect repair quality.
Solution Approach 2:
The patent establishes continuous useful action by ensuring that protons injected from the back surface can continuously reach and repair defects throughout the semiconductor substrate without being blocked. This continuous effective action reduces the need for repeated thermal processing steps, lowering manufacturing costs while maintaining high repair quality.
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 repairs defects and reduces manufacturing costs by minimizing the number of thermal processing steps while improving the semiconductor device's performance by lowering leak current and stabilizing the gate threshold voltage.
Implementation Method 1
injecting protons into a semiconductor substrate and then annealing the semiconductor substrate
Implementation Method 2
protons spread from the n-type impurity region may repair defects remaining within the semiconductor substrate
Implementation Method 3
A barrier metal used for an emitter electrode has an effect of shielding the semiconductor substrate from the protons being injected thereto
Implementation Method 4
injecting protons into a semiconductor substrate and then annealing the semiconductor substrate
Implementation Method 5
performing thermal processing, and then repairing defects by injecting protons
Data Source
AI summary
Protons are injected from a back surface side of a semiconductor substrate to repair both defects within the semiconductor substrate and also defects in a channel forming region on a front surface side of the semiconductor substrate. As a result, variation in gate threshold voltage is reduced and leak current when a reverse voltage is applied is reduced. Provided is a semiconductor device including a semiconductor substrate that includes an n-type impurity region containing protons, on a back surface side thereof; and a barrier metal that has an effect of shielding from protons, on a front surface side of the semiconductor substrate.