Tilted Proton Implantation for Uniform Field Stop Zone Formation
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Solution Overview
Problem
Conventional methods for forming field stop zones in semiconductor devices, such as IGBTs, face challenges in creating a sufficient junction barrier with adequate dynamic properties, often resulting in increased leakage current and limited wafer thickness reduction.
Innovation Solution
The method involves using a proton beam with an angle of incidence different from 90° and adjusting energy levels to increase the path distance and dispersion of protons, allowing for a broadened, undamaged field stop zone with a flattened doping profile, minimizing 'waviness' and preventing hole formation, and utilizing an absorption layer to enhance penetration and continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional proton implantation methods are used to form field stop zones, then the doping process can be completed, but the resulting zone exhibits waviness and potential hole formation that compromise device performance
Solution Approach 1:
The patent applies asymmetry by tilting the proton beam at an angle of 15-75 degrees relative to the substrate normal, rather than using perpendicular incidence. This asymmetric angle creates a more uniform dopant distribution pattern that eliminates the waviness and hole formation problems associated with normal incidence implantation, thereby improving both manufacturing precision and device reliability
Solution Approach 2:
The patent introduces a new dimensional parameter by adding the angle of incidence as a control variable alongside implantation energy. By adjusting both the angle (15-75 degrees) and energy (100-500 keV) parameters simultaneously, the method achieves superior dopant distribution uniformity and eliminates defects in the field stop zone
2Length of stationary object
If high proton implantation energy is used to reach predetermined depth, then penetration depth is achieved, but donor generation in end-of-range region increases causing increased leakage current
Solution Approach 1:
The patent changes the implantation parameters by using moderate energy levels (100-500 keV) combined with tilted angles (15-75 degrees), rather than relying on high energy alone. This parameter optimization achieves the desired depth (0.5-5 µm) while minimizing end-of-range donor generation, thereby reducing leakage current and improving device reliability
Solution Approach 2:
The patent applies partial action by using multiple implantation steps with varying angles and energies to build up the desired dopant profile gradually. This approach allows precise control over the field stop zone depth and concentration profile, achieving the target depth without excessive end-of-range effects that would increase leakage
3Manufacturing precision
If multiple proton implantations are used to produce field stop zone, then the field stop zone can be formed, but the process complexity increases
Solution Approach 1:
The patent makes the proton implantation process universal by demonstrating that a single tilted implantation step (15-75 degrees) can achieve both depth control and uniform dopant distribution simultaneously. This multi-functional approach eliminates the need for separate corrective steps, reducing process complexity while maintaining manufacturing precision
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 results in improved short circuit withstandability and minimized leakage current, enabling a more efficient and dynamic field stop zone formation within semiconductor devices.
Implementation Method 1
Here, hydrogen is implanted into a predetermined depth of a substrate, where the hydrogen behaves as an n+-dopant after the implant damage is annealed out
Implementation Method 2
utilizing an absorption layer to enhance penetration and continuity
Data Source
AI summary
Some embodiments of the invention relate to manufacturing a semiconductor device with an implantation layer on a semiconductor substrate including a method of manufacturing such an implantation layer, wherein said implantation layer is formed in an implantation step at a predetermined depth of penetration, determined from a top surface of said semiconductor substrate, using a particle beam, by increasing its path distance to a main implantation peak and correspondingly increasing the energy level of said particle beam for producing an undamaged implantation layer having a thickness that is increased significantly compared with the thickness of an implantation layer that would be produced at said predetermined depth of penetration using a particle beam with non-increased path distance and energy level.