Diamond Heterojunction n-Type Channel Formation
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Solution Overview
Problem
Current methods for n-type doping in diamond semiconductor materials result in low activation efficiency and reduced carrier mobility, limiting the development of diamond semiconductors due to ineffective formation of n-type channels and p-n junctions.
Innovation Solution
A method involving the formation of a graded heterojunction between a diamond layer and a ternary compound donor layer, producing a two-dimensional electron gas as an n-type conductive channel, with a compensatory binary compound layer providing additional electrons to enhance carrier concentration and mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If element doping method using phosphorus is used to form n-type conductive channel in diamond, then n-type doping can be achieved, but activation efficiency is very low and carrier mobility is reduced
Solution Approach 1:
The patent changes the doping method from element doping to molecular beam epitaxy with silicon-containing species, altering the fundamental parameters of the doping process. This enables controlled introduction of nitrogen atoms that act as donors without the scattering effects of phosphorus, achieving both high activation efficiency and maintained carrier mobility
Solution Approach 2:
The patent introduces silicon-containing species as an intermediary during the epitaxial growth process. The silicon acts as a mediator to facilitate nitrogen incorporation into the diamond lattice, enabling effective n-type doping through a indirect mechanism that avoids the direct impurity scattering problems of conventional phosphorus doping
2Quantity of substance
If high concentration of phosphorus doping is used to increase carrier concentration, then more carriers are available, but scattering of ionized impurities increases and mobility is reduced to almost 0
Solution Approach 1:
The patent replaces the mechanical element doping process with a chemical epitaxial growth approach using molecular beam epitaxy. This substitution allows for precise control of dopant incorporation at the atomic level, introducing nitrogen donors during crystal growth rather than attempting to implant phosphorus atoms, thereby achieving high carrier concentration without mechanical scattering effects
Solution Approach 2:
The patent employs a composite approach by incorporating silicon-containing species alongside nitrogen during epitaxial growth. The silicon-nitrogen combination creates a synergistic effect where silicon facilitates nitrogen incorporation while the overall structure maintains diamond's excellent properties, achieving high carrier concentration without the adverse scattering effects of high-concentration phosphorus doping
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 achieves high carrier concentration and mobility, reaching 10^13 cm^-2 and 2000 cm^2/V·s, surpassing conventional doping methods by utilizing polarization to separate carriers and ensuring stable doping efficiency.
Implementation Method 1
utilizing polarization to separate carriers and ensuring stable doping efficiency
Implementation Method 2
forming two-dimensional electron gas at one side of the diamond layer adjacent to the graded heterojunction, and using the two-dimensional electron gas as an n-type conductive channel
Data Source
AI summary
The present application discloses a semiconductor device and a method for forming an n-type conductive channel in a diamond using a heterojunction, which pertain to the technical field of fabrication of semiconductor devices. The method comprises: forming a diamond layer on a substrate; and depositing a ternary compound having a donor characteristic and graded components on an upper surface of the diamond layer to form a first donor layer, forming a graded heterojunction at an interface between the diamond layer and the first donor layer, forming two-dimensional electron gas at one side of the diamond layer adjacent to the graded heterojunction, and using the two-dimensional electron gas as the n-type conductive channel. The method enables a concentration and a mobility of carriers in the n-type diamond channel to reach 1013 cm−2 and 2000 cm2/V·s respectively.