Mn-Doped GaN Substrate for High-Temperature Semi-Insulating Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
GaN substrates used in radio-frequency devices face challenges in maintaining high resistivity at high temperatures and ensuring excellent crystal quality, which is crucial for reliable operation in expanding high-temperature environments.
Innovation Solution
A GaN substrate doped with manganese (Mn) is developed, with a carrier activation energy of 0.7 eV or more, achieving high specific resistance and excellent crystal quality by controlling carrier concentration and mobility, even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a GaN substrate is made semi-insulating by doping with transition metal elements (Fe or Mn), then the carrier concentration decreases and resistivity increases at room temperature, but the resistivity decreases significantly at high temperatures
Solution Approach 1:
The patent changes the doping concentration parameter of Mn from conventional levels (1×10^18 to 1×10^20 atoms/cm³) to a specific optimized range (5×10^19 to 2×10^20 atoms/cm³). This parameter adjustment creates a high carrier activation energy state (≥0.7 eV) that suppresses thermal excitation of carriers, thereby maintaining high resistivity at elevated temperatures while achieving the desired semi-insulating properties at room temperature.
2Reliability
If the Mn doping concentration is increased to achieve higher resistivity, then the semi-insulating properties improve, but the crystal quality may deteriorate due to defects
Solution Approach 1:
The patent identifies and applies a specific Mn doping concentration range (5×10^19 to 2×10^20 atoms/cm³) that optimizes both semi-insulating properties and crystal quality. Within this range, the material achieves carrier activation energy of 0.7 eV or higher, which simultaneously ensures high resistivity and suppresses defect formation, resolving the trade-off between electrical properties and crystal perfection.
Solution Approach 2:
The patent replaces conventional doping approaches that rely on mechanical/chemical concentration control with a physics-based approach using carrier activation energy as the controlling parameter. By targeting Ea ≥ 0.7 eV through optimized Mn concentration, the invention substitutes traditional resistivity-based doping control with energy-state-based control, achieving better simultaneous optimization of electrical and structural 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
The Mn-doped GaN substrate maintains high resistance and excellent crystal quality, making it suitable for use in radio-frequency devices, particularly GaN-HEMTs, across a wide range of environments.
Implementation Method 1
A method for performing doping with a transition metal element has been known as a method for making a GaN substrate semi-insulating. The transition metal element acts as an acceptor, and therefore, the transition metal element compensates for a background donor unintentionally introduced into the GaN substrate, and has an effect of decreasing a carrier concentration of the GaN substrate.
Implementation Method 2
The present inventors have found that the above first object can be achieved by forming a GaN substrate by a crystal doped with Mn and having large carrier activation energy (Ea)
Data Source
AI summary
A GaN substrate doped with manganese, in which an activation energy of a carrier is 0.7 eV or more when a carrier concentration is represented by the formula (I): carrier concentration (atoms/cm3)=A×EXP(−Ea/kT). In the formula (I), A represents a proportional constant, EXP represents an exponential function, Ea represents a carrier activation energy (eV), k represents a Boltzmann constant (8.617×10−5 eV/K), and T represents a temperature (K) in Kelvin units.