Hydrogen-Containing Insulating Layer for Transistor Channel Control
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Solution Overview
Problem
The conventional self-aligned process for metal oxide semiconductor transistors has a narrow process margin in the etching process, leading to over-etching issues and difficulties in controlling the channel length, which becomes more severe with the development of large-size manufacturing technology.
Innovation Solution
A method involving the formation of a hydrogen-containing insulating layer with controlled apertures over a metal-oxide semiconductor layer, where the hydrogen concentration is increased through heat treatment or laser irradiation to define source and drain regions, allowing for a shorter channel length and higher manufacturing yield without the need for precise etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional etching process is used to form source and drain regions, then the channel length can be controlled, but the process margin is too narrow leading to over-etching and difficulty in controlling channel length
Solution Approach 1:
A hydrogen-containing insulating layer is introduced as an intermediary between the dielectric layer and the metal-oxide semiconductor layer. This layer serves as a hydrogen source that diffuses into the semiconductor layer during heat treatment, forming highly doped source and drain regions. The intermediary layer enables precise control of doping concentration and distribution without relying on conventional etching processes, thereby achieving narrow channel lengths with adequate process margin.
Solution Approach 2:
The invention changes the doping parameter by using hydrogen diffusion through controlled heat treatment rather than conventional ion implantation or in-situ doping. By adjusting heat treatment temperature, time, and the composition of the hydrogen-containing insulating layer, the doping concentration and depth can be precisely controlled. This parameter change approach allows for forming source and drain regions with exact hydrogen concentration profiles without over-etching issues.
2Reliability
If the channel length is reduced to improve electrical performance, then carrier mobility increases, but the etching process becomes even more difficult to control
Solution Approach 1:
The hydrogen-containing insulating layer is formed in advance with apertures positioned where source and drain regions are desired. The apertures are formed with precise dimensions and positions before the heat treatment step. During subsequent heat treatment, hydrogen diffuses from this pre-positioned layer into the metal-oxide semiconductor layer, creating source and drain regions with precisely controlled locations and dimensions. This preliminary action enables narrow channel lengths to be achieved with accurate control, independent of etching process variations.
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 reduces parasitic capacitances and enhances electrical performance by allowing for precise control of the channel length, increasing manufacturing yield and avoiding over-etching problems, while maintaining semiconductor characteristics even after high-temperature treatments.
Implementation Method 1
increasing a hydrogen concentration of a portion of the metal-oxide semiconductor layer by treating the hydrogen-containing insulating layer
Implementation Method 2
treating the hydrogen-containing insulating layer so as to form a source region and a drain region
Implementation Method 3
increasing a hydrogen concentration of a portion of the metal-oxide semiconductor layer by treating the hydrogen-containing insulating layer
Data Source
AI summary
A method of manufacturing a transistor, includes: (i) forming a metal-oxide semiconductor layer over a substrate; (ii) forming a source electrode and a drain electrode on different sides of the metal-oxide semiconductor layer; (iii) forming a dielectric layer over the source electrode, the drain electrode, and the metal-oxide semiconductor layer; (iv) forming a hydrogen-containing insulating layer over the dielectric layer, in which the hydrogen-containing insulating layer has an aperture exposing a surface of the dielectric layer, and the aperture is overlapped with the metal-oxide semiconductor layer when viewed in a direction perpendicular to the surface; (v) increasing a hydrogen concentration of a portion of the metal-oxide semiconductor layer by treating the hydrogen-containing insulating layer so to form a source region and a drain region; and (vi) forming a gate electrode in the aperture.