[23a-A202-1~10] 6.2 Carbon-based thin films

▼ [23a-A202-2] Alternative Carbon-based Ohmic Electrodes for Phosphorus-doped Diamond-electronics Applications

〇(D)Sreenath Mylo Valappil^1,2, Shinya Ohmagari^2,3, Abdelrahman Zkria¹, Phongsaphak Sittimart^1,2, Eslam Abubakr¹, Hiromitsu Kato³, Tsuyoshi Yoshitake¹ (1.Dept. Of Applied Science for Electronics and Materials, Kyushu Univ., Fukuoka 816-8580, Japan, 2.Sensing System Research Center, AIST, 807-1 Shuku-machi, Tosu, Saga 841-0052, Japan., 3.Advanced Power Electronics Research Center, AIST, 1-1-1 Umezono, Tsukuba 305-8568, Japan.)

Keywords:Ohmic contacts, Phosphorus doped diamond

In this study, We report highly adhesive, thermally stable, and chemically inert nanocarbon-based ohmic electrodes exhibiting high carrier collection efficiency than Ti ohmic electrodes for phosphorus-doped diamond. The nanocarbon electrodes were fabricated through coaxial arc plasma deposition. The room temperature specific contact resistance obtained through circular transmission line model (cTLM) theory based on inter-electrode differential resistance has shown significant reduction for nanocarbon electrodes (ρ_c= 1×10^-3 Ωcm²) when compared with Ti electrodes (ρ_c= 1×10^-2 Ωcm²) at an intermediate voltage range (5V-10V). The detailed study using the constant current inter-electrode resistance extraction approach in cTLM theory has shown reduced interfacial potential drop for nanocarbon electrodes. The nanocarbon electrodes were found to be electrically active after 500 minutes of H₂SO₄+HNO₃ (3:1) treatment at 250^oC. The performance consistency of nanocarbon electrodes without capping metallization can facilitate the fabrication procedure. In the aspect of device fabrication, Ni/n-type Schottky diode exhibits a large rectification ratio as well as fast charge collection achieved at lower biasing voltage with nanocarbon electrodes as shown below. This actively suggests the nanocarbon electrodes for lightly phosphorus-doped diamond-based electronics.