Oxide Semiconductor Column Structure for Lower Gate Leakage
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Solution Overview
Problem
The manufacturing process of semiconductor devices with metal oxide electrodes faces challenges in producing high-quality semiconductor devices due to issues such as silicon whisker generation and gate leakage, which affect the reliability and performance of the devices.
Innovation Solution
The implementation of a semiconductor device configuration that includes an oxide semiconductor column with specific electrode and insulating film arrangements, such as a gate electrode surrounding the oxide semiconductor column and insulating films with different etch rates, to prevent silicon whisker formation and reduce gate leakage, along with a manufacturing method that involves precise layer deposition and etching to form a stepped surface and adjust the position of insulating films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal oxides comprising indium and tin are used for electrodes in semiconductor elements, then the electrical performance and conductivity of the device are improved, but silicon whisker generation occurs which compromises device reliability
Solution Approach 1:
An oxide insulating film is introduced as an intermediary layer between the metal oxide electrode and the semiconductor layer. This intermediate oxide layer prevents direct contact that would otherwise cause silicon whisker generation, while still allowing electrical functionality to be maintained through the insulating oxide barrier.
Solution Approach 2:
The harmful interaction between the metal oxide electrode and semiconductor layer is extracted by separating them with an oxide insulating film. This extraction removes the source of silicon whisker generation while preserving the beneficial electrical properties of the metal oxide electrode.
2Reliability
If conventional manufacturing processes are used for semiconductor devices with metal oxide electrodes, then the manufacturing complexity is reduced, but gate leakage occurs which degrades device performance
Solution Approach 1:
The oxide insulating film is formed preliminarily before depositing the metal oxide electrode. This preliminary action of creating the protective oxide layer prevents gate leakage from occurring during subsequent manufacturing steps, ensuring device performance without requiring complex post-processing corrections.
Solution Approach 2:
The structure employs composite materials by combining the metal oxide electrode with an oxide insulating film layer. This composite structure leverages the electrical properties of metal oxides while using the insulating oxide properties to prevent gate leakage, achieving high performance through material composition rather than complex processing.
3Area of stationary object
If the gate electrode is positioned close to the oxide semiconductor column to reduce device area, then the device area is minimized, but gate leakage increases which affects device reliability
Solution Approach 1:
The oxide insulating film serves as a mediator between the gate electrode and the oxide semiconductor column. This intermediate layer allows the gate electrode to be positioned close to the semiconductor for miniaturization while preventing direct harmful interactions that would cause gate leakage, thus maintaining reliability at small dimensions.
Data Source
AI summary
According to one embodiment a semiconductor device includes an oxide semiconductor column that extends in a first direction. A first electrode contacts a first end of the oxide semiconductor column and a second electrode contacts a second end. A gate electrode surrounds a portion of the oxide semiconductor column. A first insulating film is between the gate electrode and the oxide semiconductor column. A second insulating film is between the gate electrode and the first electrode in the first direction and surrounds the oxide semiconductor column via the first insulating film. A region in which at least a part of the oxide semiconductor column is accommodated is formed by the gate electrode and the second insulating film, and the region has a stepped surface facing towards the second electrode.