The Mechanism of mosfet damage induced by neutron radiation resulting from D-T fusion reaction

AMIR, Haider F. Abdul, Promotor Prof.Dr.Ir. Prayoto, MSc

2002 | Disertasi | S3 Teknik Mesin-UGM

Tujuan utama studi ini adalah memberikan informasi dan data mengenai kerusakan piranti MOS akibat radiasi neutron hasil reaksi fusi Deuteriwn-Tritium (DT). Piranti silikon Metal Oxide Semiconductor (MOS) telah menjadi piranti dasar dalam dunia industri mikro-elektronika modern. Namun, jika radiasi atau partikel bermuatan menembus suatu piranti MOS, maka kinerja dan umur operasi piranti tersebut mengalami degradasi. Radiasi neutron menyebabkan karakteristik piranti berbasis MOS berubah secara signifikan akibat penjebakan muatan pada daerah dioksida dan tertangkapnya muatan pada daerah antarmuka. Degradasi gain arus MOSFET GF4936 kanal-n tipe deplesi yang disebabkan oleh kerusakan pergeseran neutron, telah diukur dengan metode in-situ selama iradiasi neutron berlangsung. Degradasi rerata gain arus adalah sekitar 35 mA, dan perubahan pada gain arus kana1 nai k sebanding dengan kenaikan fluens neutron. Transconductance merupakan parameter gain MOSFET yang behubungan dengan fluens neutron. Transconductance ini mengalami degradasi sebesar 15,85 S, dan faktor penguatan MOSFET berkurang 10%. Total kenrsakan pergeseran oleh neutron ditemukan sebesar 4,8~10-~dp' a per n/cm2, sedangkan rerata fiaksi kerusakan kristal silikon ditemukan sebesar 1,24 x 10-l2. Semua Piranti MOSFET telah diujicoba setelah diiradiasi, dan ditemukan dalam keadaan baik tanpa terjadi kerusakan yang permanen sampai pada fluens 10'' n/cm2. Untuk mengkonfimasikan efek-efek neutron pada piranti MOS dilakukan perhitungan simulasi dan hasilnya menunjukkan bahwa reaksi (n, a) dan reaksi atom rekoil mengakibatkan soft-error cross-section masing-masing sekitar 8,7 x cm2, serta tidak ditemukan error yang berarti pada MOS kapasitor yang disebabkan oleh proton sampai pada fluens 1,0 x 10'' n/cm2. Maka dapat disimpulkan bahwa patikei alfa mengakibatkan jumlah error paling besar pada kapasitor MOS di antara ketiga partikel tersebut.

The main purpose of this study is to provide the knowledge and data on Deuterium-Tritium (D-T) hsion neutron induced damage in MOS devices. Silicon Metal Oxide Semiconductor (MOS) devices are currently the cornerstone of the modern microelectronics industry, However, when a MOS device is exposed to a flux of energetic radiation or particIes, the resulting effects from this radiation can cause several degradation of the device performance and of its operating life. Neutron radiation causes significant changes in the characteristics of MOS devices by the creation of oxide-trapped charge and interface traps. The degradation of the current gain of the GF4936 dual n-channel depletion mode MOSFET, caused by neutron displacement defects, was measured itsing in-situ method during neutron irradiation. The average degradation of the gain of the current is about 35 mA, and the change in channel current gain increased proportionally with neutron fluence. Transconductance is a gain parameter of the MOSFET and the neutron fluence at which the transconductance degraded by 15.85 S, and the amplification factor also decreased by 10%. The total fksion neutron displacement damage was found to be 4.8 x I O - ~ ’ dpa per n/cm2, while the average fiaction of damage in the crystal of silicon was found to be 1.24 x All the MOSFET devices tested were found to be controllable after neutron irradiation and no permanent damage was caused by neutron fluence irradiation below 10” n/cm2. In order to confirm the neutron damage effect, the simulation calculation was carried out. The calculation results shows that (n, a) reaction induced soft-error cross-section about 8.7 x cm2, and for recoil atoms about 2.9 x cm2, respectively. There was no error of the MOS capacitor device configuration induced by proton particles until 1.0 x 10” n/cm2 neutron fluence (simulation). Thus, it can be concluded that alpha particles induced the largest portion of error in MOS capacitor among the three kinds of charged particles.

Kata Kunci : Radiasi Neutron,Kerusakan Piranti MOS, Neutron displacement damage, Softerror, In-situ method, MOS capacitor, and MOSFET