Semiconductor Diode Channel Stopper for Withstand Voltage
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Solution Overview
Problem
Semiconductor devices with p-n junction diodes on silicon on insulator substrates face challenges in increasing the withstand voltage due to the accumulation layer formation under negative surge voltages, which limits the depletion layer spread and junction withstand voltage.
Innovation Solution
Incorporating a channel stopper region with opposite conductivity type to the contact region, arranged under the wiring between the contact region and the element isolation region, to suppress accumulation layer generation and enhance depletion layer spread, thereby increasing the junction withstand voltage of the p-n junction diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a p-n junction diode is formed on a silicon on insulator substrate with an element isolation region, then the diode can be electrically isolated from other elements, but an accumulation layer forms under negative surge voltage which limits the depletion layer spread and reduces the junction withstand voltage
Solution Approach 1:
A channel stopper region is introduced as an intermediary structure between the element isolation region and the anode region. This channel stopper region, formed with a specific conductivity type and impurity concentration, acts as a mediator that prevents the formation of accumulation layers under negative surge voltage conditions, thereby enabling the depletion layer to spread effectively and increasing the junction withstand voltage of the p-n junction diode
2Reliability
If the anode region is formed with low impurity concentration, then the p-n junction diode can be formed, but a contact region with higher impurity concentration must be interposed to reduce connection resistance, increasing device complexity
Solution Approach 1:
The channel stopper region is formed with locally optimized properties - a specific conductivity type and impurity concentration that is higher than the anode region but controlled to prevent accumulation layer formation. This local quality adjustment in the channel stopper region simultaneously achieves both the electrical isolation function and the prevention of accumulation layers, simplifying the overall device structure while maintaining low connection resistance
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
The channel stopper region effectively prevents accumulation layer formation, allowing the depletion layer to spread further, thereby increasing the junction withstand voltage of the p-n junction diode, even under negative surge conditions, through a simple configuration.
Implementation Method 1
an accumulation layer is generated below the wiring at a portion on a main face of the anode region between the contact region and the element isolation region
Implementation Method 2
a depletion layer does not spread from the element isolation region to the contact region within the anode region
Data Source
AI summary
A semiconductor device including a protected element, a contact region, wiring, and a channel stopper region. The protected element is configured including a p-n junction diode between an anode region and a cathode region, and is arranged in an active layer of a substrate. The periphery of the diode is surrounded by an element isolation region. The contact region is arranged at a portion on a main face of the anode region, and is set with a same conductivity type as the anode region, and set with a higher impurity concentration than the anode region. The wiring is arranged over the diode. One end portion of the wiring is connected to the contact region and another end portion extends over a passivation film. The channel stopper region is arranged at a portion on the main face of the anode region under the wiring between the contact region and the element isolation region, and is set with an opposite conductivity type to the contact region.