Farklı kapı oksitli RadFET dozimetrelerinin ışınlama öncesi elektriksel karakteristiklerinin TCAD benzetim programı ile değerlendirilmesi

Bu çalışmanın amacı, kapı oksiti yüksek-k’lı dielektriklerden oluşan RadFET dozimetrelerinin ışınlama öncesi eşik gerilimlerini belirlemek ve sonuçları, kapı oksiti SiO2’den oluşan geleneksel sensörlerle kıyaslamaktır. Ayrıca çalışmada, farklı konsantrasyonlu, derinlikli ve genişlikli p+ bölgelerinin RadFET’lerin elektriksel karakteristiği üzerine etkileri de incelenmiştir. Bu amaçla, dozimetrelerin duyar bölgeleri olarak 400 nm kalınlığında yüksek-k’lı Al2O3, HfO2 dielektrikleri ve SiO2 kullanılmıştır. Sensörler, Silvaco TCAD benzetim programında tasarlanmıştır. p+ bölgelerinin uzunlukları, Id-Vg karakteristiğini değiştirirken, bu bölgelerin derinlikleri ve belirli bir değere kadar konsantrasyonları elektriksel karakteristikte önemli bir rol oynamamıştır. SiO2, Al2O3 ve HfO2-RadFET’lerden elde edilen en düşük eşik voltajları sırasıyla, -5.22, -3.63 ve -3.10 V olarak bulunmuştur. Bu sonuçlar, yüksek-k dielektrikli RadFET’lerin, radyasyon testlerinin yapılması koşuluyla, daha geniş ölçülebilir doz aralığı açısından yeni nesil dozimetreler için gelecek vaat eden bir aday olduğunu göstermektedir.

Anahtar Kelimeler:

RADFET, TCAD, Yüksek-k, Eşik voltajı

Evaluation of the pre-irradiation electrical characteristics of the RadFET dosimeters with diverse gate oxides by TCAD simulation program

The aim of the present study is to determine the pre-irradiation threshold voltages of the RadFET dosimeters with gate oxide composed of high-k dielectrics and compare the results with the traditional sensors, the gate oxide of which is composed of SiO2. The effects of the p+ regions with different concentration, depth and length on the electrical characteristic of the RadFETs were also investigated in the study. For these purposes, Al2O3, HfO2 high-k dielectrics and SiO2 with the thicknesses of 400 nm were used as the sensitive regions of the dosimeters. The sensors were designed in the Silvaco TCAD simulation program. While the lengths of the p+ regions changed the Id-Vg characteristics of the RADFETs, the depths and concentrations until a certain value of these regions did not play an important role in electrical characteristic. The lowest threshold voltages obtained from the SiO2, Al2O3 and HfO2-RadFETs were found to be -5.22, -3.63, and -3.10 V, respectively. These results demonstrated that RadFETs with high-k dielectrics may be promising candidate for the new generated dosimeters in terms of broader measurable dose range providing their radiation tests.

Keywords:

RADFET, TCAD, High-k, Threshold voltage,

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