Reduced electron mobility due to nitrogen implant prior to the gate oxide growth

Abstract

We have found that nitrogen incorporation in the gate-oxide, by implantation into the Si, degrades the low field inversion mobility. Although submicron transistors fabricated using nitrogen implantation have been reported to show higher drive currents compared with "pure" oxides, we have measured about 20% degradation in large area transistors for a 2e14 cm 2 nitrogen implant. These measurements were done using nMOS transistors with thin gate-oxides ( 4 nm). Thickness determination was done by simulation fit to capacitance-voltage (C-V) measurements by including quantization and tunneling effects. We furthermore, observed that the decrease in the mobility has an increased sensitivity to the channel doping concentration.

Process optimization of plasma nitridation SiON for 65 nm node gate dielectrics

“…One can notice that plasma nitridation SiON presents the improvement on the peak effective electron mobility compared with RTNO counterpart. Unlike the previous result [4], the peak electron mobility is about 10% higher than RTNO. This could be the result of the reduction of coulomb scattering in the interface due to the nitrogen located far away from Si/SiO 2 interface by DPN process.…”

“…The oxide nitridation have been proven to be a viable means for enhancing the dielectrics strength. One of the main drawbacks of oxide nitridation is the reported degradation of carrier mobility, attributed to the enhancement of coulomb scattering with ionized impurities and charged interface states [4]. In order to realize the demand of ultra-thin gate dielectrics with low leakage and high reliability, incorporation of nitrogen into SiO 2 film must be optimized.…”

Systematical Study of Reliability Issues in Plasma-Nitrided and Thermally Nitrided Oxides for Advanced Dual-Gate Oxide p-Channel Metal–Oxide–Semiconductor Field-Effect Transistors

“…The degradation of the carrier mobility of TNO is attributed to the high interface trap density at the TNO SiO 2 /sub-Si interface and/or the enhancement of coulomb scattering caused by a high nitrogen concentration. 17,18) Consequently, PMOSFET devices with PNO exhibit a higher driving current than those with TNO. The electrical I d -V d character-istics of the PNO and TNO core PMOSFETs are plotted in Fig.…”

The Effect of Nitrogen Concentration at Oxynitride Gate Insulators Formed by 28N2 + Implantation into Silicon with Additional Conventional or Rapid Thermal Oxidation

“…Silicon oxynitride (SiO x N y ) became a promising material for sub-micron MOS thin gate insulators due to its high radiation hardness, low defect density, low gate threshold shifts and low impurity diffusion [1][2][3][4][5]. The improved dielectric reliability is mainly due to the pile up of the incorporated nitrogen in the vicinity of the SiO 2 /Si interface.…”

“…The Si-N bonds replace the strained Si-O bonds at the SiO 2 /Si interface, decreasing the interface strain [6]. Several silicon oxide nitridation techniques have been widely investigated [1][2][3][4][5][6]. Nowadays, much attention has been directed to nitridation by nitrogen or nitric oxide ion implantation [2,5,[7][8][9][10][11][12][13].…”