Semiconductor Charge Compensation Structure for On-Resistance Reduction
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Solution Overview
Problem
The production of high-blocking power transistors with minimal on resistance is hindered by the lateral spreading of charge compensation regions, which increases current density and makes it difficult to achieve a minimum step width between drift and charge compensation zones, leading to undesirable modulation of space charge and increased process variations.
Innovation Solution
The semiconductor device employs non-doped to lightly doped epitaxial growth zones with ion-implanted doping material zones of complementary conduction types over the entire surface, allowing for selective introduction of doping materials to minimize step width and reduce electric field ripple, thereby avoiding voltage peaks and maintaining avalanche tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the step width between drift zones and charge compensation zones is reduced to minimize on resistance, then the specific on resistance decreases, but the lateral spreading of compensation regions increases making minimum step width difficult to achieve
Solution Approach 1:
The patent applies preliminary action by introducing the complementary doping material through ion implantation before the diffusion process begins. The ion-implanted doping material zones are positioned in the epitaxial growth zones towards the substrate, establishing the compensation regions in advance. This preliminary placement allows control over the final distribution after diffusion, enabling minimum step width achievement while preventing excessive lateral spreading.
Solution Approach 2:
The patent employs parameter changes by controlling the diffusion process parameters and ion implantation conditions. By adjusting the diffusion time, temperature, and ion implantation dose, the patent optimizes the distribution of doping materials to achieve minimal step width while maintaining stable compensation region boundaries and preventing excessive lateral spreading.
2Manufacturing precision
If the step width between drift zones and charge compensation zones is reduced, then on resistance decreases, but the current density automatically increases causing serious modulation of space charge in avalanche situations
Solution Approach 1:
The patent applies local quality by creating regions with different doping characteristics. The ion-implanted doping material zones towards the substrate provide localized compensation exactly where needed, creating a non-uniform doping profile that optimizes the electric field distribution. This localized approach allows minimal step width while maintaining proper space charge modulation characteristics in avalanche situations through precise local control of carrier concentration.
3Shape
If masked implantation is used to introduce both types of doping material, then the shape of the p-n junction becomes nearly vertical with few bulges, but considerably more doping material has to be introduced increasing fluctuations in the production process
Solution Approach 1:
The patent extracts the problematic masking step by introducing the complementary doping material through ion implantation directly into the epitaxial growth zones without requiring masks. This extraction of the masking process eliminates the source of doping material fluctuations while still achieving the desired vertical p-n junction shape through controlled diffusion of the ion-implanted material.
4Stability of the object's composition
If the diffusion process is excessively long to achieve proper doping distribution, then the doping materials diffuse into complementary doping material regions neutralizing each other, but more doping material is required leading to increased fluctuations
Solution Approach 1:
The patent applies preliminary action by pre-positioning the doping materials through ion implantation in specific zones before diffusion begins. The ion-implanted doping material zones are strategically placed towards the substrate in the epitaxial growth zones, creating initial concentration gradients that guide the diffusion process. This preliminary arrangement ensures that during diffusion, materials move to their intended locations without excessive neutralization, reducing the total doping material required and minimizing fluctuations.
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 enables the reduction of on resistance and electric field ripple, improving the robustness and reliability of semiconductor devices by minimizing doping material fluctuations and maintaining avalanche tolerance without the need for additional epitaxial layers.
Implementation Method 1
Towards the substrate, the epitaxial growth zones include a first conduction type ion-implanted over the entire surface and selectively introduced doping material zones of the second, complementary conduction type
Implementation Method 2
the masked implanted doping material is in the diffusion process incorporated into the homogeneously doped epitaxial growth zone to virtually the same degree both laterally and vertically
Implementation Method 3
The semiconductor body includes drift zones of a first conduction type with a semiconductor material applied epitaxially in epitaxial growth zones
Data Source
AI summary
A semiconductor device with a charge carrier compensation structure in a semiconductor body and to a method for its production. The semiconductor body includes drift zones of a first conduction type and charge compensation zones of a second conduction type complementing the first conduction type. The drift zones include a semiconductor material applied in epitaxial growth zones, wherein the epitaxial growth zones include an epitaxially grown semiconductor material which is non-doped to lightly doped. Towards the substrate, the epitaxial growth zones are provided with a first conduction type incorporated by ion implantation over the entire surface and with selectively introduced doping material zones of a second, complementary conduction type. Towards the front side, the epitaxial growth zones are provided with a second, complementary conduction type incorporated by ion implantation over the entire surface and with selectively introduced doping material zones of the first conduction type.