Transition Metal Layer for SiC Ohmic Contact Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor device manufacturing methods face challenges in forming ohmic contacts on silicon carbide substrates, including uneven heating, degradation of interface properties, and reduced throughput due to the need for precise laser irradiation and flat device surfaces.
Innovation Solution
A method involving ion injection to form an impurity region, followed by the deposition of a transition metal layer and exposure to a hydrogen plasma atmosphere, where the transition metal layer generates heat to form a silicide ohmic contact and activate the impurity region, without heating other device components, thus allowing for selective and efficient heating even on non-flat surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser irradiation is used to selectively heat a predetermined area, then interface properties are preserved, but the device surface must be flat and precise positioning is required
Solution Approach 1:
The patent employs the self-service principle by utilizing the transition metal layer itself as the laser absorption layer. The transition metal layer has inherent high laser absorption properties, eliminating the need for separate absorption layers or complex positioning mechanisms. The laser beam naturally concentrates heat where the transition metal layer is located, achieving selective heating without requiring precise positioning of non-flat surfaces.
2Reliability
If high temperature heat treatment is performed to form an ohmic contact, then the contact resistivity decreases, but other device materials and interface properties degrade
Solution Approach 1:
The patent applies local quality by concentrating the high temperature heat treatment effect only in the region where the transition metal layer is located. The laser beam irradiates specifically the transition metal layer, generating high temperature locally to reduce contact resistivity, while other device materials and interface regions remain at lower temperatures and are protected from degradation.
Solution Approach 2:
The transition metal layer serves as an intermediary that absorbs the laser energy and converts it to thermal energy locally. This intermediary layer enables the high temperature heat treatment to be confined to its location, facilitating ohmic contact formation without directly exposing other device materials to high temperature conditions that would cause degradation.
3Adaptability or versatility
If the transition metal layer is disposed in a trench side wall or chip side wall, then device integration is improved, but uniform laser heating becomes difficult
Solution Approach 1:
The patent applies self-service by using the transition metal layer's inherent laser absorption characteristics to automatically concentrate heat where needed, regardless of the underlying surface topology. Whether the transition metal layer is on a flat surface, trench side wall, or chip side wall, the laser energy is absorbed where the transition metal layer exists, ensuring uniform heating of the layer itself and the underlying region without requiring the surface to be flat.
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 method simplifies the manufacturing process, improves throughput, and prevents degradation of device properties by ensuring only the transition metal layer generates heat, forming a silicide layer with low contact resistivity and maintaining interface integrity.
Implementation Method 1
exposing the semiconductor substrate with the transition metal layer formed thereon, to a hydrogen plasma atmosphere formed by microwaves
Implementation Method 2
by a transfer of heat from the transition metal layer, the impurity region is heated forming at an interface of the transition metal layer and the impurity region
Implementation Method 3
forming at an interface of the transition metal layer and the impurity region, an ohmic contact by a reaction of the transition metal layer and the impurity region
Data Source
AI summary
A method of manufacturing a semiconductor device that reduces degradation of device properties includes forming an impurity region in a surface layer of a semiconductor substrate by ion injection; forming a transition metal layer in a surface of the impurity region; and exposing the semiconductor substrate with the transition metal layer formed thereon to a hydrogen plasma atmosphere formed by microwaves. The transition metal layer is heated and the heat is transferred from the transition metal layer to the impurity region to form an ohmic contact at the interface of the transition metal layer and the impurity region by reaction of the transition metal layer and the impurity region, and the impurity region is activated. When the substrate is a silicon carbide substrate, the ohmic contact is composed of a transition metal silicide and the impurity region, which is an ion injection layer, is activated.