Study on Resistivity Changes of Local Material Silicon Wafer Doped with Neutron Transmutation Doping (NTD) Using Multi Purpose Nuclear Reactor (MPR-30)

Abstract

Study on resistivity changes of local material silicon wafer, doped with Neutron Transmutation Doping (NTD) using Multi Purpose Nuclear Reactor (MPR-30) was carried out. Two kinds of local material of intrinsic silicon wafer were used as samples for this experiment. These local silicon wafers have no shallow doping. The first have resistivity of between (0.7960 – 0.8010) Ω cm (sample 1). The second have resistivity of between (18.6000 – 33.0000) Ω cm (sample 2). The samples were cleaned with distilled water, and acetone. The samples were sprayed with high pure nitrogen gas. The natural oxide layer on the surface of the local silicon wafer was etched with HF for 1 until 3 minutes. The local silicon wafer was inserted into the aluminum tube. The diameter of aluminum tube was 7 inch. High of aluminum tube was 40 cm. The position of the sample 1 was in the aluminum tube 4 cm that was lower than in the sample 2. The local silicon wafers were irradiated with thermal neutron, in Neutron Transmutation Doping (NDT) facility, in research nuclear reactor MPR-30 (Multi Purpose Reactor-30), Indonesia. The power reactor for the experiment was 15 Mega Watt (MW). The thermal neutron flux was 1012neutron cm-2s-1. The irradiation time was 264 hours. After irradiated samples, the local silicon wafers were annealed at a temperature of 7000C, for one hour. The resistivity of local silicon wafers before and after irradiated, measured by four-point probe. The results showed that average resistivity of sample 1 before the irradiated was 0.8120 Ω cm, and after irradiation its resistivity decreased to 0.0673 Ω cm. The average resistivity of sample 2 before the irradiated was 20.4890 Ω cm, and after irradiation its resistivity decreased to 0.9730 Ω cm. The resistivity of sample 1 and sample 2 after irradiation were homogeneous, it means that the doped phosphorus concentrations also homogeneous.