Diamond Power Transistors Enabled by Phosphorus Doped Diamond

Project: Research project

Description

Compared to all other semiconductors considered for power electronics, diamond exhibits the largest bandgap, highest hole and electron mobilities, highest breakdown field, and largest thermal conductivity. Recent advances using phosphorus for n-type doping have established the potential of vertical p-n-p and p-n-i-p power devices based on epitaxial diamond layers.
However, two significant challenges for diamond power electronics are growth of uniformly Pdoped diamond and development of low resistance contacts to the doped layers. These challenges are the focus of this seedling project where P-doped diamond will be prepared using plasma assisted growth with in situ doping. The doping uniformity will be related to substrate orientation, growth rate and defect structure. The breakdown field will be established for p-n-p and p-n-i-p structures. Contacts to n-type diamond are difficult because the material exhibits a work function of ~1eV. Novel contact approaches will include doped nanocrystalline diamond, doped boron nitride, and ultra thin insulating layers, and I-V properties will be characterized vs. temperatures. The performance of p-n-p and p-n-i-p devices will be simulated based on the
measured results. Diamond represents the ultimate power electronics disruptive technology, and the focus of this project is on two of the greatest challenges.

Description

Project Abstract Compared to all other semiconductors considered for power electronics, diamond exhibits the largest bandgap, highest hole and electron mobilities, highest breakdown field, and largest thermal conductivity. Recent advances using phosphorus for n-type doping have established the potential of vertical p-n-p and p-n-i-p power devices based on epitaxial diamond layers. However, two significant challenges for diamond power electronics are growth of uniformly Pdoped diamond and development of low resistance contacts to the doped layers. These challenges are the focus of this seedling project where P-doped diamond will be prepared using plasma assisted growth with in situ doping. The doping uniformity will be related to substrate orientation, growth rate and defect structure. The breakdown field will be established for p-n-p and p-n-i-p structures. Contacts to n-type diamond are difficult because the material exhibits a work function of ~1eV. Novel contact approaches will include doped nanocrystalline diamond, doped boron nitride, and ultra thin insulating layers, and I-V properties will be characterized vs. temperatures. The performance of p-n-p and p-n-i-p devices will be simulated based on the measured results. Diamond represents the ultimate power electronics disruptive technology, and the focus of this project is on two of the greatest challenges

Description

This document requests a 3 month extension of the ARPA-E project on Diamond Electronics and Detectors. The goal of this extension is to fabricate and demonstrate neutron detectors based on optimized diamond pin detectors. The project is based on our prior results which have established that pin diamond diodes with a 5 um thick i-layer are optimized to detect the alpha particle generated by neutron absorption in a boron containing conversion layer.

The extension will accomplish the following:
1) Diamond pin diodes with 5 um thick i-layers will be fabricated on (111) p-type diamond plates and characterized using the Po source and the ASU radiation testing system.
2) A boron nitride conversion layer will be deposited on the top contact of the diodes that display expected performance. The BN/pin-diamond detector will be characterized using the Po source and the ASU radiation testing system. The results will be analyzed and compared to simulations that combine radiation interactions and semiconductor device properties.
3) Selected detectors will be tested using a thermal or cold neutron source from NIST and/or other characterization facilities. The results will be analyzed and compared to simulations that combine radiation interactions and semiconductor device properties.

We have been in discussion with NIST and have preliminary agreement to characterize our detectors. We are also exploring options for testing the detectors on other neutron sources.

We are requesting $110,718 for the extension, and ASU will provide cost sharing of $5,951 of the total project cost of $116,669. A budget summary and justification follows.
StatusFinished
Effective start/end date2/20/147/15/19

Funding

  • DOE: Advanced Research Projects Agency-Energy (ARPA-E): $2,303,865.00

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phosphorus
transistors
diamonds
electronics
detectors
boron nitrides
breakdown
diodes
low resistance
hole mobility
radiation
neutron sources
semiconductor devices
electron mobility
thermal conductivity
costs
cold neutrons
neutron counters
defects
thermal neutrons