1. Prof. Yonhua Tzeng
Diamond and Devices Lab
Department of Electrical Engineering
National Cheng Kung University
Diamond & Devices Lab
成功大學與德國烏爾姆大學合作
Collaboration between NCKU (Taiwan) and Ulm University (Germany)
(1.) Hydrogen generation with transparent boron doped diamond (BDD) electrodes
(a.) Diamond electrodes on sapphire
(b.) Diamond electrodes on silicon membrane
Nanodiamond for electrochemical and high power electronic applications
Fabrication of electrodes on silicon
 bias-enhanced nucleation (BEN)
 growth of diamond films in HFCVD
 E-beam lithography and thermal
evaporator to form metallic clusters
 etching of silicon to form diamond membrane
Motivation
Diamond is an electrochemically stable
electrode material and is an transparent
layer on a semiconductor solar cell
 immerse a solar cell panel in water
with gas bubbles floating off from the
surface.
 it does not corrode in the cathodic
regime and does not form an oxide
layer under anodic polarization.
 neither cathodic nor anodic
polarization leads to etching of
diamond
Modifying diamond electrodes by metallic
micro dots to reduce the water splitting
redox potential window (3V)
 metallic clusters on diamond surface
need to be stable in expected
operating environments
 the metallic clusters can narrow the
potential window with remaining
diamond electrode staying transparent
Transparent diamond film
 inductively coupled plasma etching
 sulfur hexafluoride gas
Publications
Cyclic voltammetry of boron doped
diamond electrode and boron doped
diamond modified by titanium and
platinum micro dots 0.25 % and 11%
surface coverage.
Narrow the potential window
Enhance the current density
Electrochemical measurement
cluster diameter: 2 µm
distance: 6 µm
surface coverage: 11%
Optical microscope photo
Poster# P130
C. Li, Y. Tzeng, E. Kohn, M. Dipalo C.Liu,
“Electrochemical and Optical Properties
of Electrode with A Metallic Microdot
Array on Boron Doped Diamond.”
Poster# P176
 Z. Gao, Y. Xu, C. Pietzka, E. Kohn,
“Water Splitting with Transparent
Diamond Electrodes.”
(2.) Investigation of diamond nucleation
-- Comparison of electrochemical activities of nanodiamond deposited on silicon with diamond seeding and bias enhanced nucleation
(3.) (a) lnAIN growth on GaN at NCKU (b) Diamond seeding and growth at NCKU (c) Patterning and fabrication of HEMT at Ulm
Growth temp. 750 °C
Gas conc. 0.3 % CH4 in H2
Growth rate 0.12 µm/hr
InAlN/GaN HEMT on sapphire
- 200 nm Si3N4 passivation
- standard metallization
Processed in Ulm
Motivation
Publications
Motivation
BDD
Intrinsic Diamond
Sapphire Substrate
Diamond Seeding
After 500 nm growth
Results
Seeding with nano particles(NCKU)
Fabrication of HEMT (Ulm)
MOCVD growth of lnAIN/GaN on
sapphire (NCKU)
Device and materials analysis
(Ulm and NCKU)
Heat sink
-4 -3 -2 -1 0 1 2 3
-20
-15
-10
-5
0
5
10
15
20
Currentdensity(mA/cm2
)
Potential vs Ag/AgCl (voltage)
BDD/Ti/Pt (0.25% coverage)
BDD/Ti/Pt (11% coverage)
BDD
No microdots
11% coverage by microdots
0.25% coverage by microdots
Transmittance spectrum
Diamond for heat extraction
Poster# P147
 Z. Gao, Y. Lin, E. Colombo, Y. Liu, Y. Tzeng, E. Kohn,“Effects of
Seeding, BEN and CVD Processes on Optical Transparency of
Quasi-metallically Doped NCD Electrodes Grown on Insulating
Substrates.”
 joint posters at 4th NDNC (New Diamond
and Nano Carbons) conference in China,
May 16-20, 2010
Si
NCD
BDD 1 μm
1 μm
500μm
Si
Ti
Pt
 Diamond films on transparent substrate
are important for bio-MEMs
 Deposition of Diamond films on non-
diamond substrates needs seeding by
nanodiamond particles or nucleation from
carbide clusters (metal carbides or SiC)
 Carbide clusters are not transparent but
form a stable interface
 Seeding by nanodiamond particles does
not hinder transparency but is
challenging to form a stable interface with
the substrate, compromising adhesion.
Contribution to existing EU-FP7
project MORGAN.
Improve the cooling capability of a
GaN power FET.
 Thermal management of GaN power
FETs by a top diamond heat spreader
using NCKU seeding method for
diamond layer growth.
0 2 4 6 8 10 12
0.0
0.1
0.2
0.3
0.4
0.5
0.6
-7 V
LG
= 0.5 痠
-6 V
-5 V
-2 V
VDS
(V)
IDS
(A/mm)
-4 V
-3 V
-1 V
0 V
1 V
2 V
3 Vμm
 Participation in MORGAN follow-up project proposed
Prof. Erhard Kohn
Materials and Devices Group
Inst. of Electron Devices and Circuits
Ulm University
joint poster at 4th NDNC (New Diamond and Nano Carbons)
conference in China, May 16-20, 2010
Acknowledgement
Financial support by NSC Taiwan under the grants (NSC-98-3114-M-
006-001, NSC-96-2221-E-006-286-MY3, NSC-98-2911-I-006-031,
NSC-99-2915-I-006-015) is highly appreciated.
• Only Seeding (NCKU)
• Seeding (NCKU) + MPCVD (NCKU)
• BEN(Ulm) + MPCVD (Ulm)
1 μm nano-crystal diamond (NCD)
1 μm boron doped diamond
Sapphire Substrate
Diamond Seeding