A New Method for Extracting the Radiation Induced Trapped Charge Density Along the STI Sidewall in the PDSOI NMOSFETs

Author

Chao Peng ; Zhiyuan Hu ; Zhengxuan Zhang ; Huixiang Huang ; Bingxu Ning ; Dawei Bi ; Shichang Zou

Author_Institution

State Key Lab. of Functional Mater. for Inf., Shanghai Inst. of Microsyst. & Inf. Technol., Shanghai, China

Volume

60

Issue

6

fYear

2013

fDate

Dec. 2013

Firstpage

4697

Lastpage

4704

Abstract

The effects of the radiation-induced trapped charge in shallow trench isolation (STI) and buried oxide (BOX) on total ionizing radiation response of 0.13 μm partially-depleted silicon-on-insulator (PDSOI) NMOS technology are analyzed respectively. The positive trapped charge in the STI oxide, but not in the BOX, is responsible for the off-state leakage increase after ON bias radiation. A new method is proposed to calculate the surface charge density along the STI sidewall. This method takes into account the influences of the non-uniform electric field and the variable oxide thickness in the STI region. Moreover, the calculated non-uniform charge density along the STI sidewall is verified by three dimensional simulations. Even though there is charge-accumulation in the BOX, it shows minimal impact on the front-gate characteristics of the PDSOI devices in this 0.13 μm technology, except for the device with low body doping concentration. The positive charge trapped in BOX can induce significant threshold voltage shift in the RVT (regular Vth) I/O NMOSFET through coupling effect.

Keywords

MOSFET; doping profiles; elemental semiconductors; isolation technology; radiation effects; semiconductor device models; silicon; silicon-on-insulator; NMOS technology; ON bias radiation; PDSOI NMOSFET; RVT; STI sidewall; Si; buried oxide; charge-accumulation; coupling effect; front-gate characteristics; low body doping concentration; nonuniform charge density; nonuniform electric field; off-state leakage; partially-depleted silicon-on-insulator; positive trapped charge; radiation induced trapped charge density; shallow trench isolation; size 13 mum; surface charge density; three dimensional simulations; threshold voltage shift; total ionizing radiation response; variable oxide thickness; Doping; Leakage currents; Logic gates; MOSFET; Semiconductor process modeling; Silicon-on-insulator; Threshold voltage; Buried oxide; PDSOI NMOS; charge density; coupling effect; off-state leakage current; oxide trapped charge; shallow trench isolation (STI); total ionizing dose;

fLanguage

English

Journal_Title

Nuclear Science, IEEE Transactions on

Publisher

ieee

ISSN

0018-9499

Type

jour

DOI

10.1109/TNS.2013.2283504

Filename

6651757