Nitride Semiconductor Crystal Doping with Carbon and Oxygen
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Solution Overview
Problem
Current methods for producing nitride semiconductor crystals using metal organic chemical vapor deposition struggle with achieving high carrier concentration and activation rate for p-type conductivity, particularly due to the difficulty in controlling acceptor dopant distribution and activation energy, leading to inefficient doping and temperature-dependent properties.
Innovation Solution
Introducing carbon (C) and oxygen (O) atoms simultaneously into the crystal using a metal organic chemical vapor deposition process with organic compounds having specific partial structures like C—C—O, C—C═O, and C—O—C, which allows for reliable placement of C and O atoms as acceptors and donors, enabling efficient p-type conductivity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Mg is used as acceptor dopant to control p-type conductivity, then the nitride semiconductor can achieve p-type conductivity, but the carrier concentration cannot be increased sufficiently and activation rate remains at several percent
Solution Approach 1:
The patent combines multiple dopants (Mg as acceptor, Si or Ge as donors) into a single doping process. By introducing both acceptor and donor dopants simultaneously during crystal growth, the system achieves high carrier concentration through donor dopants while maintaining p-type conductivity through the acceptor dopant, resolving the contradiction between reliable p-type control and sufficient carrier concentration.
Solution Approach 2:
The patent creates a composite doping structure where multiple dopant elements (Mg, Si, Ge) are introduced together to form a multi-component doped semiconductor. This composite approach allows the synergistic effect of different dopants: Mg provides p-type conductivity control while Si or Ge provide high carrier concentration, achieving both objectives simultaneously.
2Quantity of substance
If high carrier concentration is attempted with conventional doping, then carrier concentration can be increased, but acceptor dopant activation rate remains at several percent and further increase is difficult
Solution Approach 1:
The patent introduces donor dopants (Si, Ge) as intermediaries that facilitate the activation of acceptor dopants (Mg). The donor dopants create a favorable electronic environment that enhances the activation efficiency of Mg acceptors, allowing high carrier concentration to be achieved while maintaining high acceptor activation rates through the mediating effect of donor elements.
3Reliability
If conventional p-type doping is used, then Mg can be introduced as acceptor dopant, but the dopant level is typically deep (exceeding 100 meV) resulting in low activation rate at room temperature and large temperature dependence
Solution Approach 1:
The patent changes the doping parameters by introducing donor dopants (Si, Ge) in combination with Mg acceptor dopant. This parameter change creates a modified doping profile where the presence of donor elements alters the electronic structure and reduces the acceptor energy level from deep (>100 meV) to shallower levels, thereby reducing temperature dependence and improving room temperature activation rate while maintaining p-type conductivity.
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 high carrier concentration and activation rate with a shallow acceptor level, reducing temperature dependence and improving the efficiency and stability of p-type nitride semiconductor properties, suitable for various electronic devices.
Implementation Method 1
a method of producing a nitride semiconductor crystal by a metal organic chemical vapor deposition process
Data Source
AI summary
A method of producing a nitride semiconductor crystal uses a metal organic chemical vapor deposition process and offers good controllability with respect to a p-type nitride semiconductor crystal. To that end, an organic metal compound of a group III element, a hydride of nitrogen, and an organic compound having any of the partial structures C—C—O, C—C═O, C═C—O, C═C═O, C≡C—O, and C—O—C are used as source materials, and by a metal organic chemical vapor deposition process, C and O atoms are simultaneously introduced into the crystal to obtain p-type conductivity.