FinFET Diode Junction Electric Field Enhancement
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Solution Overview
Problem
Existing semiconductor diodes face challenges in increasing junction electric fields without elevating dopant concentrations beyond 10^19 cm^-3, as higher dopant concentrations lead to ionized impurity scattering, which reduces carrier mobility.
Innovation Solution
The development of diode structures for FinFET technologies with high electric fields is achieved by forming fins on a semiconductor substrate with N and P channel doped regions, where the N channel dopant concentration is greater than the P channel dopant concentration, and the junction is located at the base or below the fin, allowing for increased electric fields without excessive dopant levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If dopant concentrations are increased to increase junction electric field, then diode forward current is improved, but carrier mobility deteriorates due to ionized impurity scattering
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping profile where the dopant concentration varies spatially within the semiconductor region. Specifically, the doping concentration is higher near the junction interface and decreases toward the bulk, allowing the electric field to be enhanced locally at the junction without uniformly increasing dopant concentration throughout the entire structure. This localized approach maintains carrier mobility in the bulk while achieving high electric field at the junction for improved forward current.
Solution Approach 2:
The patent changes the doping profile parameter from a uniform concentration to a graded or non-uniform distribution. By modifying the spatial distribution of dopants rather than simply increasing the overall concentration, the patent achieves higher junction electric field through parameter optimization. The doping concentration gradient allows the electric field to be maximized at the critical junction region while keeping average dopant concentration low enough to maintain acceptable carrier mobility.
2Force
If dopant concentrations are increased beyond 10^19 cm^-3 to increase electric field, then junction electric field is improved, but ionized impurity scattering increases
Solution Approach 1:
The patent concentrates the dopant distribution locally at the junction region rather than uniformly throughout the semiconductor. This creates a high electric field precisely where needed at the junction interface without distributing the harmful ionized impurities throughout the entire carrier transport path. The localized high concentration region is confined to minimize its impact on overall carrier mobility while achieving the desired electric field strength.
Solution Approach 2:
The patent converts the potentially harmful effect of high dopant concentration into a beneficial localized electric field enhancement. By strategically placing high dopant concentration only at the junction region, the patent transforms what would normally be a source of scattering (ionized impurities) into a useful tool for creating the desired high electric field, while the surrounding lower-doped regions maintain good carrier transport properties.
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 results in higher diode forward current and capacitance, with increased electric field strength and drive current, effectively enhancing diode performance without the drawbacks of high dopant concentrations.
Implementation Method 1
an electric field across a junction arises from the diffusion of electrons from the N channel doped region to the P channel doped region and the diffusion of holes in the opposite direction
Implementation Method 2
a P channel doped region (i.e., a region comprising a P-type dopant, i.e., a source of holes) adjacent to an N channel doped region (i.e., a region comprising an N-type dopant, i.e., a source of electrons)
Data Source
AI summary
Diodes for use in FinFET technologies having increased junction electric fields without the need for increased dopant concentrations, as well as methods, apparatus, and systems for fabricating such diodes. The diodes may comprise a semiconductor substrate and a plurality of fins formed on the semiconductor substrate; wherein each of the plurality of fins comprises an N channel doped region comprising an N channel dopant, and the semiconductor substrate further comprises a plurality of P channel doped regions comprising a P channel dopant, wherein each of the P channel doped regions is disposed under one of the plurality of fins and is adjacent to the N channel doped region of the fin.