A Comparative Study of Defect Energy Distribution and Its Impact on Degradation Kinetics in GeO₂/Ge and SiON/Si pMOSFETs

Abstract

Abstract-High mobility germanium (Ge) channel is considered as a strong candidate for replacing the Si in pMOSFETs in near future. It has been reported that the conventional power-law degradation kinetics of Si devices is inapplicable to Ge. In this work, further investigation is carried out on defect energy distribution, which clearly shows that this is because the defects in GeO 2 /Ge and SiON/Si devices have different physical properties. Three main differences are: 1) Energy alternating defects (EAD) exist in Ge devices but insignificant in Si; 2) The distribution of as-grown hole traps (AHT) has a tail in the Ge band gap but not in Si, which plays an important role in degradation kinetics and device lifetime prediction; 3) EAD generation in Ge devices requires the injected charge carriers to overcome a 2 nd energy barrier, but not in Si. Taking the above differences into account, the power law kinetics of EAD generation can be successfully restored by following a new procedure, which can assist in the Ge process/device optimization.

Cumulative degradation methodology to predict reliability of electronic systems

“…In this paper, the degradation is modeled using the (normalized) power law equation: where M is the normalized performance metric of interest, C 1 and N are the model fit parameters which in this instance are shown as functions of temperature. Such power law dependence is observed for degradation of contact resistance of mechanical switches (McLinn, 2016), trapping/de-trapping of charge carriers at the gate oxide interface in CMOS devices (Ma et al , 2016), or creep of solder joints (Kumar et al , 2012). This performance metric could be similarly modeled as a function of other environmental stressors like humidity, voltage, current, etc.…”

A Comparative Study of AC Positive Bias Temperature Instability of Germanium nMOSFETs With GeO₂/Ge and Si-cap/Ge Gate Stack

“…Content may change prior to final publication. can be categorized into three types: Generated Defects (GD), As-grown Traps (AT), and Energy Alternating Defects (EAD) [14,15,19,27]. GD cannot discharge under 0V and follow the same generation kinetics against effective stress time under DC/AC stress [28], thus can be excluded from the origin of "additional DC generation".…”

Research progress in Ge-based advanced field effect transistor technology

“…实验表明, GeO 2 是较为理想的 high-k/Ge 界面钝化层, high-k/GeO 2 /Ge 的界 面态密度低, 能够提供较高的载流子迁移率 [8] . 但是, 与传统 Si 器件中的硅氧化物 (SiO 2 ) 相比, GeO 2 极不稳定 [9] , 易溶于水, 在空气中会发生降解. 同时, GeO 的禁带宽度比 GeO 2 小 [10] , 引入 GeO 会增 加栅极堆垛中的慢界面态, 严重影响器件的可靠性 (如图 2 所示).…”