Nitric acid compensated aluminum oxide dielectrics with improved negative bias reliability and positive bias temperature response

Abstract

The room-temperature nitric acid (HNO3) compensation method is introduced to effectively improve the dielectric quality of ultrathin aluminum oxide (Al2O3) gate dielectrics under low thermal budget consideration. The physical properties, electrical characteristics, and temperature response of Al2O3 metal-oxide-semiconductor (MOS) devices without and with HNO3 compensation are compared. The surface roughness and interface trap density are obviously decreased by utilizing HNO3 compensation. Under negative gate bias, the leakage current, hard breakdown characteristics, and temperature-dependent reliability of the Al2O3 MOS(p) capacitors are clearly improved by HNO3 compensation. Under positive gate bias, the highly temperature-dependent current is principally dominated by generation-recombination mechanism. However, the diodes without HNO3 compensation show irregular temperature response especially at temperature above 70 °C. From Frenkel-Poole emission analysis, the oxide traps in Al2O3 without HNO3 compensation are responsible to this abnormal temperature response. These results suggest that the quality of ultrathin Al2O3 gate dielectrics can be cost-effectively improved by HNO3 compensation.

Al₂O₃ Obtained through Resistive Evaporation for Use as Insulating Layer in Transparent Field Effect Transistor

“…Research on field effect transistors (FET) requires insulating materials with high-quality properties, which can be used for replacing silicon dioxide (SiO 2 ) in the role of gate layer [1][2][3]. Aluminum oxide (Al 2 O 3 ) is an insulator material with crescent use as dielectric gate, tunneling barrier and protection coating [1,4].…”

“…Aluminum oxide (Al 2 O 3 ) is an insulator material with crescent use as dielectric gate, tunneling barrier and protection coating [1,4]. It has been distinguished from other oxides due to several interesting properties such as high dielectric constant (high-k), large band gap, high adherence to several sort of semiconductor materials and good thermal and mechanical stability [1][2][3][4], being suitable to be used as dielectric gate, where it shows low leakage current and low density of interface defects. Its large band gap is suitable for building heterojunctions with wide band gap semiconductors such as SnO 2 [5], due to the band offset between these materials.…”

Heterojunction between Al2O3 and SnO2 thin films for application in transparent FET

“…In this scenery, aluminum oxide presents interesting properties such as: high dielectric constant, wide bandgap, high corrosion resistance and high adhesion to various types of materials. These properties allow this oxide to be used as tunneling barrier [8][9][10] , dielectric gate and protective coatings in FET devices 3,6 . Concerning its combination with SnO 2 , it must be mentioned the large band offset, which is an important parameter for the coupling semiconductor / insulating related to the insulation in a FET device.…”

“…The search for alternative materials to silicon dioxide for use in electronic devices has grown in the past recent years [1][2][3] , related to a reduction in energy consumption and greater control of electric current in field-effect transistor (FET) devices 2 . It concerns the seek for insulating materials with appropriate properties, such as higher values of dielectric constant (high-k) for use in the gate terminal, allowing reduction of leakage current [1][2][3][4][5][6][7] .…”

“…It concerns the seek for insulating materials with appropriate properties, such as higher values of dielectric constant (high-k) for use in the gate terminal, allowing reduction of leakage current [1][2][3][4][5][6][7] . In this scenery, aluminum oxide presents interesting properties such as: high dielectric constant, wide bandgap, high corrosion resistance and high adhesion to various types of materials.…”