Semiconductor Diode Shield Region for High Voltage Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices with silicon on insulator (SOI) substrates face challenges in increasing the withstand voltage of p-n junction diodes without affecting the characteristics of other elements, such as MOSFETs, due to the need for lower impurity concentrations in the p-type active layer.
Innovation Solution
A semiconductor device design that includes a p-n junction diode with an element isolation region, a contact region, and a shield region, where the contact region has a higher impurity concentration than the anode region and the shield region has an opposite conductivity type, allowing the depletion layer to spread and increase the junction withstand voltage without altering other element characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the impurity concentration of the anode region is lowered to enable depletion layer spread, then the junction withstand voltage is increased, but the contact resistance increases
Solution Approach 1:
The patent creates a contact region with high impurity concentration (1E19 to 1E21 atoms/cm³) at the specific location where electrical contact is needed, while maintaining lower impurity concentration in other areas. This localized high impurity region provides low contact resistance for electrical connection, while the shield region with high impurity concentration enables depletion layer spread for increased withstand voltage.
Solution Approach 2:
The anode region is segmented into different functional zones: a contact region with high impurity concentration for low resistance electrical contact, and a shield region with high impurity concentration that enables depletion layer spread. This segmentation allows each region to fulfill its specific function without compromising the other.
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 effectively increases the junction withstand voltage of the p-n junction diode without impacting the characteristics of other elements, such as MOSFETs, by allowing the depletion layer to spread along the shield region and detour around it, thus enhancing the device's voltage handling capabilities.
Implementation Method 1
Supposing a negative surge voltage were applied to the anode region. Setting the impurity concentration of the anode region lower would enable a depletion layer to spread from the p-n junction toward the anode region, enabling the junction withstand voltage of the p-n junction diode to be increased.
Data Source
AI summary
A semiconductor device including a protected element, an element isolation region, a contact region, and a shield 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. A periphery of the diode is surrounded by the element isolation region. The contact region is arranged at a portion on a main face of the anode region, is set with a same conductivity type as the anode region, and is set with a higher impurity concentration than the anode region. The shield region is arranged between the cathode region and the contact region so as to extend from the main face of the anode region as far as a region deeper than a depth of the contact region and shallower than the anode region. The shield region is configured including a semiconductor region with an opposite conductivity type to the anode region.