Oxide Semiconductor Transistor Structure With TaN Bonding Control
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving high on-state current, low power consumption, and small variation in electrical characteristics, particularly in transistors, while maintaining reliability and scalability.
Innovation Solution
A semiconductor device structure is developed with specific layers, including an oxide semiconductor layer and conductive layers containing tantalum and nitrogen, where the tantalum bonding states are optimized to enhance electrical performance, and the use of a surrounded channel structure to improve current density and field-effect mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional semiconductor structures are used, then manufacturing is simpler, but on-state current is insufficient
Solution Approach 1:
The device is divided into multiple functional layers including oxide semiconductor layer, conductive layers with specific tantalum bonding states, and insulating layers. Each layer performs a specific function to collectively achieve high on-state current while maintaining manageable manufacturing complexity through modular structure
Solution Approach 2:
The patent applies local quality by optimizing specific regions with tailored properties: oxide semiconductor layer in contact region for high current density, conductive layers with controlled tantalum bonding states (30-70% Ta-N bonds) for localized electrical performance enhancement, and insulating layers for electrical isolation where needed
2Productivity
If transistor density is increased, then integration is improved, but variation in electrical characteristics increases
Solution Approach 1:
The patent controls critical parameters including tantalum bonding state composition (30-70% Ta-N bonds), oxide semiconductor layer thickness and composition, and heat treatment conditions to maintain electrical characteristic uniformity across integrated devices while enabling higher density through scaled dimensions
Solution Approach 2:
Heat treatment is applied preliminarily to stabilize the oxide semiconductor layer and control tantalum bonding states before final device assembly and integration. This preliminary stabilization ensures uniform electrical characteristics are established early, preventing variation propagation through subsequent manufacturing steps
3Use of energy by moving object
If power consumption is reduced, then energy efficiency is improved, but on-state current decreases
Solution Approach 1:
The device uses composite material structure combining oxide semiconductor with specific tantalum-containing conductive layers. The oxide semiconductor provides low off-state current (low leakage) while the optimized conductive layers with controlled Ta-N bonding states maintain high on-state current, achieving both low power consumption and high drive current capability
Solution Approach 2:
By changing the bonding state parameters of tantalum (controlling the ratio of Ta-N bonds to 30-70%), the device optimizes the balance between on-state current and off-state current. This parameter control enables the transistor to achieve high on/off current ratio, simultaneously improving power efficiency and maintaining drive current
Data Source
AI summary
A semiconductor device having excellent electrical characteristics is provided. The semiconductor device includes a first conductive layer, a first insulating layer over the first conductive layer, an oxide semiconductor layer over the first insulating layer, a second conductive layer, a third conductive layer, and a second insulating layer over the oxide semiconductor layer, and a fourth conductive layer over the second insulating layer. The second conductive layer and the third conductive layer each contain tantalum and nitrogen. In each of the second conductive layer and the third conductive layer, the percentage of a first tantalum bonding state is lower than or equal to 3%, and the percentage of a second tantalum bonding state is higher than or equal to 5%. The first tantalum bonding state is a bonding state of tantalum metal and a bonding state of tantalum nitride with stoichiometrically less nitrogen per tantalum, and the second tantalum bonding state is a bonding state of tantalum nitride with stoichiometrically equal nitrogen per tantalum.