GaN-HEMT on 100mm
Diameter Sapphire Substrate Grown by MOVPE
Yohei Otoki, *Michio
Kihara, *Takeshi Tanaka, *Kazuto Takano, **Toshihide Kikkawa and
***Tsutomu Igarashi
Semiconductor
Engineering Dept.,
Phone:
+81-2-9442-5071 Fax: +81-2-9442-6410 E-mail: otoki.yohei@hitachi-cable.co.jp
*Advanced
**Fujitsu
Laboratories Ltd, ***Fujitsu Quantum Devices Ltd.
Keywords: GaN-HEMTs, 100mm
diameter, sapphire substrate, MOVPE, uniformity, DC characteristics
Abstract
Possibility of using
GaN-HEMT grown by MOVPE on 100mm sapphire substrates in the industry has been
investigated. Bowing of 2 µm thick GaN on 100mm substrate was 40 to 60 µm. Excellent uniformity of sheet carrier
concentration of HEMT structure wafer across the wafer was obtained by
optimizing the gas flow system and thermal circumstance to avoid pre-reaction
between Ammonia and III group gases. FETs with 0.8 µm gate were well fabricated in spite of the
bowing and good pinch-off characteristics and high breakdown voltage over 100V
was obtained. Standard deviation of Vth was 50mV across the wafer (average
Vth=-2.6V), that of Idss and Gm-max were 11mA (average Idss=300mA/mm) and 5.3mS
(average Gm-max=145mS /mm), respectively. This uniformity is good enough for
mass production. These results are very encouraging as they show the high
possibility to successfully achieve mass production of 100mm wafers.