Silicon Carbide Device Silicide Contact Resistance
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Solution Overview
Problem
Conventional silicon carbide semiconductor devices, such as MISFETs, face challenges in reducing on-resistance and manufacturing cost, particularly in forming silicide contacts where abnormal growth of metal silicide occurs due to the reaction between polysilicon and metal films, leading to increased complexity and cost in the manufacturing process.
Innovation Solution
A silicon carbide semiconductor device configuration that includes a substrate with a silicon carbide semiconductor layer, insulating layers, and silicide electrodes, where the second silicide electrode is designed to cover the entire bottom surface of the opening part and have a wider width than the opening part, and is formed through a process involving thermal treatment to create a silicide contact with the polysilicon electrode layer, thereby reducing contact resistance and suppressing abnormal growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a metal film is formed on the polysilicon electrode layer to create a silicide contact, then contact resistance is reduced, but abnormal growth of metal silicide occurs leading to increased manufacturing complexity and cost
Solution Approach 1:
The patent applies preliminary action by forming the silicide layer directly on the polysilicon electrode layer before forming the insulating layer. This preliminary silicidation prevents abnormal silicide growth later and eliminates the need for complex subsequent processing steps to control silicide formation, thereby reducing manufacturing complexity while maintaining low contact resistance
Solution Approach 2:
The patent extracts the silicide formation step from the later processing stages and performs it early when the polysilicon layer is exposed. By taking out the silicidation step and performing it before insulating layer formation, the patent avoids the abnormal growth issues that occur when metal films are deposited later, simplifying the overall manufacturing process
2Ease of manufacture
If the second silicide electrode is formed with the same width as the opening part, then the manufacturing process is simpler, but metal diffusion into the polysilicon layer occurs causing abnormal growth
Solution Approach 1:
The patent applies preliminary anti-action by forming the silicide layer in advance before the insulating layer is deposited. This preliminary formation creates a stable silicide structure that prevents subsequent metal diffusion into the polysilicon layer, even when the electrode width matches the opening part width, thereby preventing abnormal growth without complicating the manufacturing process
Solution Approach 2:
By performing the silicidation action before insulating layer formation, the patent establishes a controlled silicide structure early in the process. This preliminary action prevents metal diffusion issues that would otherwise require additional processing steps, maintaining manufacturing simplicity while ensuring reliability
3Power
If silicon carbide is used instead of silicon, then breakdown voltage increases and on-resistance decreases, but manufacturing cost increases
Solution Approach 1:
The patent merges the silicide formation process with the existing polysilicon electrode layer structure. By utilizing the polysilicon layer already present in the SiC device and forming silicide directly on it, the patent eliminates the need for separate metal film deposition and silicidation steps, thereby reducing manufacturing cost while maintaining the high breakdown voltage and low on-resistance benefits of SiC
Solution Approach 2:
The patent applies self-service by using the polysilicon electrode layer itself as the substrate for silicide formation. The polysilicon layer serves dual purposes: as the electrode structure and as the base for silicide formation. This self-service approach eliminates the need for additional metal films and complex processing, reducing manufacturing cost while preserving SiC's superior electrical properties
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 configuration effectively reduces on-resistance and power loss while lowering the manufacturing cost by simplifying the process and preventing metal diffusion into the polysilicon layer, thus enhancing the reliability and efficiency of the semiconductor device.
Implementation Method 1
a first silicide electrode is formed by causing the metal film and the silicon carbide semiconductor layer to react with each other in the first opening part through thermal treatment of the substrate
Implementation Method 2
a second silicide electrode is formed by causing the metal film and the polysilicon electrode layer to react with each other in the second opening part
Implementation Method 3
through thermal treatment of the substrate
Data Source
AI summary
Provided is a silicon carbide semiconductor device that is further reduced in resistance. Silicon carbide semiconductor device includes silicon carbide semiconductor layer disposed on a first main surface of substrate, electrode layer containing polysilicon disposed on the silicon carbide semiconductor layer with first insulating layer interposed between the electrode layer and the silicon carbide semiconductor layer, second insulating layer that covers the silicon carbide semiconductor layer and the electrode layer, first silicide electrode that is located in first opening part formed in the first insulating layer and the second insulating layer and forms ohmic contact with a part of the silicon carbide semiconductor layer, and second silicide electrode that is located in second opening part formed in the second insulating layer and is in contact with a part of the electrode layer.