Evaluation of stress-induced effect on electronic characteristics of nMOSFETs using mechanical stress simulation and drift-diffusion device simulation

Author(s):  
M. Koganemaru ◽  
T. Ikeda ◽  
M. Komori ◽  
N. Miyazaki ◽  
H. Tomokage
Author(s):  
Masaaki Koganemaru ◽  
Keisuke Yoshida ◽  
Toru Ikeda ◽  
Noriyuki Miyazaki ◽  
Hajime Tomokage

An electrical characteristic of a semiconductor device suffers from a residual stress during various packaging processes. Very few attempts have been made at developing a numerical method for evaluating such problems. Therefore, the objective of this study is to evaluate stress-induced effects by numerical simulation. That is, the effects of stress on the electrical characteristics of n-type Metal Oxide Semiconductor Field Effect Transistors (nMOSFETs) with a 85nm gate length were evaluated by mechanical stress simulation and drift-diffusion device simulation (multi-physics simulation). The device simulation model used includes the electron mobility model that considers the stress-induced effects. This study focused on the impact of the stress distribution in the nMOSFETs. The stress distribution in the nMOSFETs was considered in conducting the multi-physics simulation. As determined by mechanical stress simulation, stress concentrated around the STI, and the effect of such stress concentration reached the channel region of the nMOSFETs. Then, the drift-diffusion device simulation was carried out. The stress distribution in the nMOSFETs obtained by mechanical stress simulation was used as the stress effect in the device simulation model. As determined by device simulation, the drain current decreased under the estimated residual stress. The drain-current shift corresponded quantitatively to the stress at the region of the channel. It was demonstrated that the multi-physics simulation is essential for evaluating the effect of stress on electrical characteristics of a semiconductor device.


Author(s):  
Masaaki Koganemaru ◽  
Naohiro Tada ◽  
Toru Ikeda ◽  
Noriyuki Miyazaki

This paper discusses a numerical model for analysing the effects of mechanical stress on semiconductor devices. In other words, drift-diffusion device simulation is conducted using a physical model incorporating the effects of mechanical stress. Then, each impact of the stress-induced physical phenomena is analysed. In our previous study, three physical phenomena that were attributed to mechanical stress have been modeled in our electron mobility model, i.e., the changes in relative population, the momentum relaxation time and the effective mass of electrons in conduction-band valleys. In addition, in this study, the stress-induced change of intrinsic carrier density is modeled. Stress-induce variations of drain current characteristics on n-type Metal Oxide Semiconductor Field Effect Transistors (nMOSFETs) are evaluated using a drift-diffusion device simulator including above mentioned physical models. It is demonstrated that the impact of stress-induced change of intrinsic carrier density is small for our evaluated nMOSFETs.


2021 ◽  
Author(s):  
Wenqi Li ◽  
Chaoyang Xing ◽  
Jianfeng Zhang ◽  
Ziji Wang ◽  
Zhaoxi Su ◽  
...  

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2559 ◽  
Author(s):  
Nobuyuki Sano ◽  
Katsuhisa Yoshida ◽  
Chih-Wei Yao ◽  
Hiroshi Watanabe

Localized impurities doped in the semiconductor substrate of nanostructure devices play anessential role in understanding and resolving transport and variability issues in device characteristics.Modeling discrete impurities under the framework of device simulations is, therefore, an urgent needfor reliable prediction of device performance via device simulations. In the present paper, we discussthe details of the physics associated with localized impurities in nanostructure devices, which areinherent, yet nontrivial, to any device simulation schemes: The physical interpretation and the roleof electrostatic Coulomb potential in device simulations are clarified. We then show that a naiveintroduction of localized impurities into the Poisson equation leads to a logical inconsistency withinthe framework of the drift-diffusion simulations. We describe a systematic methodology for how totreat the Coulomb potential consistently with both the Poisson and current-continuity (transport)equations. The methodology is extended to the case of nanostructure devices so that the effects of theinterface between different materials are taken into account.


1987 ◽  
Vol 34 (2) ◽  
pp. 392-399 ◽  
Author(s):  
S. Bandyopadhyay ◽  
M.E. Klausmeier-Brown ◽  
C.M. Maziar ◽  
S. Datta ◽  
M.S. Lundstrom

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