Recess-Free AlGaN/GaN Lateral Schottky Barrier
Controlled Schottky Rectifier with Low Turn-on
Voltage and High Reverse Blocking
Xuanwu Kang
1
, Xinhua Wang
1
, Sen Huang
1
, Jinhan Zhang
1
, Jie Fan
1
, Shuo Yang
1
, Yuankun Wang
1
,
Yingkui Zheng
1
, Ke Wei
1
, Jin Zhi
1
, Xinyu Liu
1
1
Key Laboratory of Microelectronic Devices & Integrated Technology
Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, China
Email: kangxuanwu@ime.ac.cn; liuxinyu@ime.ac.cn
Abstract—High-performance AlGaN/GaN-on-Si diodes are
fabricated with lateral Schottky barrier controlled Schottky
rectifier (LSBS) on thin-barrier (5nm) AlGaN/GaN
heterostructures, which features a recess-free process,
enabling better electrostatic control to pinch off the channel
under the anode region. In this way, low leakage currents (3-
orders of magnitude lower than conventional recessed
Schottky-barrier-diode (SBD)) and a high reverse breakdown
voltage of 1700 V (@10µA/mm) are reached, together with a
low onset voltage of only 0.37 V and a record low on-state
resistance R
on,sp
of 1 mΩ∙cm
2
for GaN-based SBDs with an
Anode-to-Cathode distance (L
AC
) of 10 µm. This is attributed
to the combination of an effectively preserved 2DEG by
LPCVD SiN
x
passivation and a hybrid Schottky /Ohmic anode.
Thanks to the recess free technology and low damage in the
Schottky region, stable preliminary HTRB performance are
obtained. The proposed diode fabrication is compatible with
GaN depletion/enhancement MIS-HEMTs process flow,
enabling integration in the promising smart GaN platform.
Keywords—AlGaN/GaN, Schottky-barrier-diode, SBD, Lateral,
high breakdown voltage, low turn-on voltage
I. INTRODUCTION
GaN-based Schottky diodes are of great importance in
power switching applications, as they offer fast switching
speed, high electric field breakdown strength, and good thermal
properties [1]–[2]. The next-generation high-efficiency power
systems require diodes with a low turn on voltage, a high
breakdown voltage, and a fast switching speed. Various
structures have been proposed to reduce the turn-on voltage of
AlGaN/GaN SBDs, e.g. a recessed Schottky [2]-[3], a lateral
field-effect rectifier employing fluorine plasma treatment [4].
In addition to that, a gated ohmic anode rectifier [5], a MIS-
Gated hybrid anode rectifier [6] and gate edge terminated
Schottky diodes [3][7] are designed to reduce the turn-on
voltage and suppress the reverse leakage current. However, the
solutions [2]-[6] proposed need extra Schottky barrier
“treatment”, e.g. recess or implantation, which might introduce
Schottky barrier damage and further result in potential
reliability issues[8][9].
To get rid of extra Schottky barrier “treatment”, an recess-
free lateral Schottky barrier controlled Schottky rectifier (LSBS)
has been proposed and fabricated on thin-barrier AlGaN/GaN
heterostructures, with two-dimensional electron gas (2DEG)
being effectively preserved by SiN
x
passivation grown by low-
pressure chemical-vapor-deposition (LPCVD). The fabricated
LSBSs exhibit low onset voltage, high reverse blocking and
good stability.
This work was supported in part by the National Key R&D Program of China (No. 2016YFB0400100, No. 2017YFB0403000), in part by Natural Science
Foundation of China (No. 61334002, 61404163, 61474138, 61534007, 61527816, and 11634002), in part by the Key Project of Chinese Academy of
Sciences (No. QYZDB-SSW-JSC012 and Y7YT024002).
(a)
(b)
Fig. 1. The schematic cross-section of the recess free LSBSs and epi structure
(Al
0.25
Ga
0.75
N barrier is 5nm), where, L
SC
and L
AC
are the length of the
Schottky contact region and the drift length of the LSBS, respectively.
978-1-5386-2927-7/18/$31.00 ©2018 IEEE 280
Proceedings of the 30th International Symposium on Power Semiconductor Devices & ICs
May 13-17, 2018, Chicago, USA