Metal Oxide Deposition for Semiconductor Crystallinity
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Solution Overview
Problem
Current semiconductor devices using oxide semiconductors face challenges in achieving high on-state current, field-effect mobility, and reliability due to lattice defects and impurities, particularly oxygen vacancies and hydrogen, which affect electrical characteristics and integration miniaturization.
Innovation Solution
A deposition method involving a sequence of supplying different precursors, including indium, gallium, aluminum, yttrium, and zinc, with oxidizers, and heat treatment to form a metal oxide with a CAAC structure, reducing impurities and enhancing crystallinity, using a deposition apparatus with precise temperature control and plasma generation for improved semiconductor device manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide semiconductor is used for transistor, then device functionality is achieved, but lattice defects and impurities (oxygen vacancies, hydrogen) reduce on-state current and field-effect mobility
Solution Approach 1:
The patent applies preliminary action by performing multiple heat treatment steps before final device operation. Specifically, the oxide semiconductor layer undergoes heat treatment at 200-400°C for 1-48 hours to pre-reduce lattice defects and impurities, followed by additional heat treatment at higher temperatures (400-700°C) to further eliminate oxygen vacancies and hydrogen. This preliminary treatment sequence improves on-state current and field-effect mobility by preparing the crystal structure in advance.
Solution Approach 2:
The patent employs parameter changes by systematically varying heat treatment temperature (from 200°C to 700°C), treatment time (from 1 hour to 48 hours), and atmosphere conditions to optimize the removal of lattice defects. By adjusting these parameters, the oxide semiconductor transitions from an amorphous or poorly crystalline state to a highly crystalline state with reduced oxygen vacancies and hydrogen content, thereby improving electrical characteristics.
2Manufacturing precision
If conventional deposition methods are used, then manufacturing simplicity is maintained, but manufacturing precision and device reliability are insufficient
Solution Approach 1:
The patent applies segmentation by dividing the deposition and treatment process into distinct sequential steps: (1) deposition of oxide semiconductor layer, (2) first heat treatment at 200-400°C for 1-48 hours, (3) second heat treatment at 400-700°C, and (4) final annealing. Each step targets specific defects or structural aspects, allowing precise control over crystallinity and impurity removal while maintaining manageable process complexity.
Solution Approach 2:
The patent implements continuity of useful action by performing continuous heat treatment sequences without interrupting the manufacturing flow. The multiple heat treatment steps are conducted in succession, with each treatment building upon the previous one to progressively improve crystallinity. This continuous approach ensures that the oxide semiconductor layer maintains optimal structural properties throughout the manufacturing process.
3Productivity
If oxide semiconductors are used, then device functionality is achieved, but miniaturization and integration are hindered by insufficient electrical characteristics
Solution Approach 1:
The patent employs parameter changes by optimizing heat treatment temperature (400-700°C) and duration (1-48 hours) to achieve high crystallinity in the oxide semiconductor layer. This parameter optimization results in superior electrical characteristics including high on-state current and field-effect mobility, which are essential for miniaturized and integrated devices where performance margins are tighter.
Solution Approach 2:
The patent applies strong oxidants by using oxygen plasma or oxygen-containing atmosphere during heat treatment and annealing processes. This accelerated oxidation removes oxygen vacancies and stabilizes the oxide semiconductor crystal structure, improving electrical characteristics and enabling reliable miniaturization and integration of semiconductor devices.
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
The method results in semiconductor devices with improved electrical characteristics, high on-state current, and field-effect mobility, enhanced reliability, and the ability for miniaturization and integration, by reducing lattice defects and impurities through the formation of a crystalline metal oxide with a CAAC structure.
Implementation Method 1
a substrate placed in the chamber in the first to fourth steps is heated to a temperature higher than or equal to 300° C. and lower than or equal to a lowest temperature among decomposition temperatures of the first to third precursors
Implementation Method 2
a fourth step of introducing an oxidizer into the chamber after the first step, the second step, and the third step
Implementation Method 3
a substrate placed in the chamber in the first to fourth steps is heated to a temperature higher than or equal to 300° C. and lower than or equal to a lowest temperature among decomposition temperatures of the first to third precursors
Data Source
AI summary
A novel deposition method of a metal oxide is provided. The deposition method includes a first step of supplying a first precursor to a chamber; a second step of supplying a second precursor to the chamber; a third step of supplying a third precursor to the chamber; and a fourth step of introducing an oxidizer into the chamber after the first step, the second step, and the third step. The first to third precursors are different kinds of precursors, and a substrate placed in the chamber in the first to fourth steps is heated to a temperature higher than or equal to 300° C. and lower than or equal to decomposition temperatures of the first to third precursors.