Diamond Heterojunction p-Type Channel Stability
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Solution Overview
Problem
Conventional methods for forming p-type conductive channels in diamond semiconductor devices are prone to instability at high temperatures due to environmental sensitivity and poor thermal stability, limiting their application in high-temperature and radiation-resistant devices.
Innovation Solution
A method involving the formation of an abrupt heterojunction between a hydrogen-terminated diamond layer and an acceptor layer, utilizing a two-dimensional hole gas as a p-type conductive channel, which maintains carrier concentration and mobility stability within a temperature range of 0°C to 1000°C by leveraging the inherent polarization effect of the materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a near surface absorption layer is formed in air to create a p-type conductive channel, then a conductive channel is formed via carrier transfer, but the channel becomes unstable at high temperatures due to environmental sensitivity and desorption of polar molecules
Solution Approach 1:
The patent introduces an acceptor layer as an intermediary substance between the diamond surface and the environment. This acceptor layer forms a heterojunction that enables carrier transfer to create a p-type conductive channel, while being inherently stable at high temperatures unlike the environmentally-dependent absorption layer. The acceptor layer mediates the formation of stable two-dimensional hole gas without requiring polar molecules that desorb at elevated temperatures.
Solution Approach 2:
The patent changes the fundamental parameter of how carrier transfer is achieved - transitioning from environmental absorption of polar molecules to controlled formation of a heterojunction with an acceptor layer. This parameter change enables the conductive channel to maintain stability across a wide temperature range (0°C to 1000°C) by eliminating dependence on temperature-sensitive molecular adsorption.
2Reliability
If conventional boron doping is used to create p-type conductivity, then impurity ionization releases excess carriers, but carrier mobility is severely reduced due to ionized impurity scattering
Solution Approach 1:
The acceptor layer acts as an intermediary that enables carrier transfer without requiring high concentrations of ionized impurities in the diamond bulk. The two-dimensional hole gas formed at the heterojunction interface provides p-type conductivity through a different mechanism - carrier accumulation at the interface rather than bulk impurity ionization - thereby maintaining high carrier mobility while achieving effective p-type conduction.
Solution Approach 2:
The patent transitions from three-dimensional bulk doping to two-dimensional interface carrier accumulation. By forming the conductive channel as a two-dimensional hole gas at the heterojunction interface rather than through bulk boron doping, the system achieves p-type conductivity without the ionized impurity scattering that plagues conventional doping methods, thus preserving high carrier mobility.
3Quantity of substance
If high doping concentration is used to improve conductivity, then more carriers are available, but ionized impurity scattering increases and carrier mobility approaches zero
Solution Approach 1:
The patent achieves high effective carrier concentration through two-dimensional accumulation at the heterojunction interface rather than three-dimensional bulk doping. This dimensional transition allows sufficient carriers to be concentrated in the two-dimensional hole gas to provide effective conductivity while avoiding the ionized impurity scattering that occurs when high concentrations of dopants are distributed throughout the bulk material.
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 provides a stable p-type conductive channel with improved carrier mobility, reducing the influence of temperature and minimizing ionized impurity scattering, thus enhancing the thermal stability and performance of diamond-based high-temperature power devices.
Implementation Method 1
a near surface absorption layer is formed in the air, the near surface absorption layer contains polar molecules, such as water molecules and CO2 molecules. Due to the interaction between the C—H bonds and polar molecules of the absorption layer, a conductive p-type conductive channel is formed in a near surface layer in the diamond via carrier transfer.
Implementation Method 2
utilizing a two-dimensional hole gas as a p-type conductive channel, which maintains carrier concentration and mobility stability within a temperature range of 0°C to 1000°C by leveraging the inherent polarization effect of the materials.
Data Source
AI summary
The present application discloses a semiconductor device and a method for forming a p-type conductive channel in a diamond using an abrupt heterojunction, which pertain to the technical field of fabrication of semiconductor devices. The method includes: forming a diamond layer on a substrate; forming one or multiple layers of a heterogeneous elementary substance or compound having an acceptor characteristic on an upper surface of the diamond layer; forming a heterojunction at an interface between the diamond layer and an acceptor layer; forming two-dimensional hole gas at one side of the diamond layer with a distance of 10 nm-20 nm away from the heterojunction; and using the two-dimensional hole gas as a p-type conductive channel. The method enables a concentration and a mobility of carriers to maintain stable at a temperature range of 0° C.-1000° C., thereby realizing normal operation of the diamond device at high temperature environment.