Zener Diode Lower Diffusion Region Voltage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices with Zener diodes experience temporal fluctuations in Zener voltage due to breakdown phenomena, which are difficult to control accurately, leading to inaccurate voltage control in constant-voltage power supplies, especially in applications like vehicle-mounted monitoring ICs.
Innovation Solution
The semiconductor device incorporates a semiconductor substrate with a diode formation region, an upper diffusion region of one conductivity type, and a lower diffusion region of another conductivity type, where the lower diffusion region has a higher impurity concentration and is positioned deeper than the upper diffusion region, allowing for controlled breakdown occurrence and reduced hot carrier trapping, thereby minimizing Zener voltage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional Zener diode structure is used, then the device can provide voltage regulation function, but temporal fluctuations in Zener voltage occur due to breakdown phenomena and hot carrier trapping
Solution Approach 1:
The semiconductor device is segmented into multiple functional regions: a first doped region (N-type) and a second doped region (P-type) forming the Zener diode junction, with a third doped region (P-type) positioned adjacent to the first region. This segmentation allows the third region to act as a dedicated hot carrier collection zone, separating the breakdown occurrence location from the voltage measurement location, thereby reducing temporal fluctuations in Zener voltage.
2Ease of operation
If breakdown phenomenon is allowed to occur for voltage regulation, then voltage control function is achieved, but hot carrier trapping causes temporal variations in Zener voltage
Solution Approach 1:
The third doped region serves as an intermediary structure between the breakdown junction and the external circuit. It provides a dedicated pathway for hot carrier collection, acting as a buffer that prevents hot carriers from being trapped in the depletion region. This intermediary region enables voltage control function while mitigating the harmful effects of hot carrier trapping on voltage stability.
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 design enables precise control of breakdown occurrence and reduces temporal variations in Zener voltage, ensuring accurate voltage control and stability in constant-voltage power supplies.
Implementation Method 1
breakdown occurrence and reduced hot carrier trapping, thereby minimizing Zener voltage fluctuations
Data Source
AI summary
A semiconductor device includes: a semiconductor substrate having a diode formation region; an upper diffusion region of a first conductivity type provided on a surface layer of a main surface of the semiconductor substrate in the diode formation region; and a lower diffusion region of a second conductivity type provided at a position deeper than the upper diffusion region with respect to the main surface in a depth direction of the semiconductor substrate, the lower diffusion region having a higher impurity concentration as compared to the semiconductor substrate. The lower diffusion region provides a PN joint surface with the upper diffusion region at a position deeper than the main surface, and has a maximum point indicating a maximum concentration in an impurity concentration profile of the lower diffusion region in the diode formation region.