Field Emission Package Structure for Arc-Safe Current Density Control
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Solution Overview
Problem
Existing field emission elements face reliability issues due to probe deformation and arcing, with n-type silicon probes experiencing high current densities and p-type probes limiting current density, and manufacturing complexities in transistor integration.
Innovation Solution
A package structure integrating a p-type wafer with an LED (or LD) using a silicon on insulator (SOI) wafer, with protruding portions and insulating layers to control current density and prevent arcing, and a gate electrode to manage electron emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If n-type silicon probes are used to achieve high current density, then current density increases, but reliability deteriorates due to arcing and probe deformation
Solution Approach 1:
The patent applies local quality by creating a p-n junction structure where the probe tip region has different doping characteristics than the base. The probe tip is formed with n-type doping to enhance field emission, while the base remains p-type to provide stability. This localized differentiation allows high current density at the emission tip while maintaining overall structural reliability and preventing arcing in the base region.
Solution Approach 2:
The patent employs composite materials by combining p-type and n-type silicon regions within a single probe structure. This composite approach creates a p-n junction field emission element where the n-type tip provides high electron emission capability while the p-type base offers stability and prevents plasma generation. The composite structure resolves the contradiction by integrating the beneficial properties of both material types in specific spatial zones.
2Reliability
If p-type wafer is used to ensure reliability, then reliability improves, but current density is limited due to lack of electrons
Solution Approach 1:
The patent applies local quality by creating a p-n junction structure where the field emission tip region is locally doped with n-type material, while the bulk substrate remains p-type. This localized n-type region provides sufficient electrons for high current density field emission, while the p-type base maintains reliability by preventing plasma generation. The spatial differentiation resolves the contradiction between reliability and current density.
Solution Approach 2:
The patent transitions from a uniform one-dimensional p-type structure to a two-dimensional differentiated structure with distinct p-type and n-type regions. By adding the dimension of spatial doping variation, the patent enables the probe to simultaneously achieve reliability from the p-type base and high current density from the n-type tip region, effectively resolving the trade-off through dimensional expansion of the material structure.
3Ease of operation
If transistor is manufactured to control current, then current control improves, but probe density decreases due to complex manufacturing and additional area
Solution Approach 1:
The patent merges the field emission function and current control function into a single integrated structure. The p-n junction itself provides inherent current control through its diode characteristics, eliminating the need for separate transistor components. This merging of functions maintains high probe density while achieving reliable current control, resolving the contradiction between ease of operation and device complexity.
Solution Approach 2:
The patent applies universality by designing the p-n junction probe to perform multiple functions simultaneously: field emission, current control, and self-protection against arcing. The single structure serves as both the electron source and the current regulator, eliminating the need for additional control components. This multi-functionality reduces device complexity while maintaining ease of current control operation.
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
Enhances current density and reliability by controlling current flow through each probe, preventing arcing, and ensuring uniform electron emission.
Implementation Method 1
at least one light-emitting element disposed in a lower region of the device layer, and configured to emit light through the device layer
Implementation Method 2
In a probe-type field emission element, the field emission current density is very sensitive to a shape of a probe
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(c)
Figure 3(a)~3(c)
AI summary
A package having a field emission element may include a handle layer; a buried layer stacked on the handle layer; a device layer stacked on the buried layer; an insulating layer stacked in an upper region of the device layer; a gate electrode stacked in an upper region of the insulating layer; and at least one light-emitting element disposed in a lower region of the device layer, and configured to emit light through the device layer. The insulating layer may be configured with a plurality of insulating regions separated by first separation regions, and the gate electrode may be configured with a plurality of metal regions separated by second separation regions. The device layer may be provided with protruding portions disposed to protrude between the first separation regions between the insulating regions and the second separation regions between the metal regions.