TMDC Transistor Threshold Voltage Control via Doping
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Solution Overview
Problem
Current transistors using transition metal dichalcogenides (TMDCs) face challenges in controlling threshold voltage and reliability, particularly in achieving a positive threshold voltage and high sensitivity for flexible and transparent display applications.
Innovation Solution
A transistor design incorporating a semiconductor layer with a second material doped into a first material, expressed as XYa, where X is molybdenum, tungsten, zirconium, or rhenium, and Y is sulfur, selenium, or tellurium, with the second material being tungsten, hafnium, tantalum, titanium, platinum, nickel, or zirconium, which is used to form a layered structure with controlled doping levels to adjust the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transition metal dichalcogenides (TMDCs) are used as semiconductor material, then high mobility and thin-film thickness are achieved, but threshold voltage control and reliability are insufficient
Solution Approach 1:
The patent applies parameter changes by systematically varying the doping concentration of the second material (W, Hf, Ta, Ti, Pt, Ni, or Zr) in the semiconductor layer. By controlling the amount of second material doped into the first material (Mo, W, Zr, or Re compound), the threshold voltage can be precisely adjusted while maintaining high mobility. This resolves the contradiction by enabling reliable threshold voltage control through material composition parameters.
Solution Approach 2:
The patent uses composite materials by combining the first material (transition metal compound XYa) with the second material (doping element) to create a doped semiconductor layer. This composite structure allows the base material to provide high mobility and thin-film characteristics while the doped second material provides threshold voltage control and improved reliability, simultaneously addressing both requirements.
2Ease of operation
If doping concentration of second material is increased to control threshold voltage, then threshold voltage shifts positively, but carrier concentration decreases
Solution Approach 1:
The patent employs parameter changes by optimizing the doping concentration of the second material within specific ranges (e.g., 0.1-5 wt%, or 1-10 at%). This controlled parameter adjustment allows the threshold voltage to shift positively for better control while maintaining sufficient carrier concentration for device operation, resolving the trade-off between threshold voltage control and carrier availability.
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 approach allows for precise control of threshold voltage and improved reliability by shifting the threshold voltage positively and reducing carrier concentration, enhancing the transistor's performance in flexible and transparent display applications.
Implementation Method 1
The semiconductor layer includes a second material doped to a first material. The second material includes at least one of tungsten (W), hafnium (Hf), tantalum (Ta), titanium (Ti), platinum (Pt), nickel (Ni), gallium (Ga), or zirconium (Zr). The second material includes an element that is different from the first material.
Implementation Method 2
a gate electrode overlapping the semiconductor layer; and a source electrode and a drain electrode electrically connected to the semiconductor layer
Data Source
AI summary
A transistor includes a semiconductor layer on a substrate, a gate electrode overlapping the semiconductor layer, and a source electrode and a drain electrode electrically connected to the semiconductor layer. The semiconductor layer includes a second material doped to a first material. The first material includes a compound expressed as XYa of a Chemical Formula. X is one of Mo, W, Zr, or Re, Y is one of S, Se, or Te, and a is a natural number that is equal to or greater than 1. The second material includes at least one of W, Hf, Ta, Ti, Pt, Ni, Ga, or Zr. The second material includes an element that is different from the first material.