Fin-Based Schottky Diode with Differential Fin Heights
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Solution Overview
Problem
Manufacturing Schottky diodes based on FinFET technology has been problematic due to challenges in achieving efficient and reliable production processes.
Innovation Solution
The development of a fin-based Schottky diode for integrated circuits, involving a semiconductor substrate with anode and cathode regions featuring fins of different vertical heights, and a conductive structure that contacts the upper surface of these fins, along with a substrate contact region and doped well regions, to enhance contact and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If standard silicon diodes are used, then manufacturing is simpler, but forward voltage drop is high and switching speed is slow
Solution Approach 1:
The anode region is segmented into multiple fins instead of using a single planar structure. This segmentation increases the effective contact area between the conductive structure and the semiconductor substrate, reducing resistance and forward voltage drop while maintaining compatibility with FinFET manufacturing processes
Solution Approach 2:
The patent applies different fin heights in different regions: the anode region has fins with a first vertical height while the cathode region has fins with a second vertical height greater than the first. This local differentiation optimizes the electrical characteristics for each region, reducing forward voltage drop in the anode while maintaining proper Schottky barrier formation in the cathode
2Speed
If FinFET technology is used for Schottky diodes, then switching speed improves, but manufacturing reliability deteriorates
Solution Approach 1:
The FinFET structure is designed to serve dual functions: it provides the high switching speed characteristics needed for Schottky diodes while also being compatible with standard FinFET manufacturing processes. The exposed substrate within the anode region and the specific fin height configurations ensure reliable formation of the Schottky barrier, making the structure universally applicable to existing FinFET production lines
3Reliability
If fins of different heights are used in anode and cathode regions, then contact efficiency improves, but device complexity increases
Solution Approach 1:
The patent implements local quality by assigning different fin heights to different functional regions: the anode region uses fins with a first vertical height to optimize contact with the conductive structure, while the cathode region uses fins with a greater second vertical height to ensure proper Schottky barrier formation. This regional differentiation improves contact efficiency without requiring complex multi-step fabrication processes
Solution Approach 2:
The fin structures are pre-formed with different heights during the FinFET fabrication process itself, rather than requiring subsequent complex modification steps. The exposed substrate within the anode region is prepared in advance during fin formation, enabling reliable Schottky barrier formation without additional complex processing
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 allows for improved contact and reduced resistance in the anode region, enabling efficient and reliable production of Schottky diodes compatible with FinFET technology, suitable for various IC applications.
Implementation Method 1
a conductive structure that contacts and engages at least an upper surface of the plurality of first fins in the anode region
Implementation Method 2
an inner doped well region in the semiconductor substrate below the anode region and the cathode region, wherein the inner doped well region comprises dopant material of a first type
Data Source
AI summary
One illustrative Schottky diode disclosed herein includes a semiconductor substrate, an anode region and a cathode region. The anode region includes a plurality of first fins with a first vertical height formed in the anode region, wherein an upper surface of the semiconductor substrate is exposed within the anode region. The cathode region includes a plurality of second fins with a second vertical height that is greater than the first vertical height. The device also includes a conductive structure that contacts and engages at least an upper surface of the plurality of first fins in the anode region.