CMOSデバイスに向けたゲルマニウム基板上高誘電率絶縁膜ゲートスタック技術

CMOS器件用锗衬底高介电常数绝缘膜栅叠层技术

基本信息

批准号：
12J09309
负责人：
張睿
金额：
$ 1.28万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for JSPS Fellows
财政年份：
2012
资助国家：
日本
起止时间：
2012 至 2013
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12J09309/
关键词：
Ge MOSFETs High field mobility Carrier scattering ゲルマニウムゲートスターク MOS界面 MOSFET

项目摘要

Ge channel is one of the most promising solution for CMOS devices in post-Si age. Mobility enhancement is the most critical issue limiting the application of Ge MOSFETS. Recently, although many progresses have been achieved for high mobility Ge MOSFETs, mobility degradation in high normal field region is still severe which strongly reduces the ON state current in Ge MOSFETs. The mechanism of this phenomenon is not clear yet, in spite of importance. Therefore, in our research the physical origins causing high normal field mobility degradation were systematically investigated. Through the evaluation of Hall mobility in Ge MOSFETs, it is found that large amount of surface states exist inside valence and conduction band of Ge, which results in significant decrease of mobile carrier concentration in the channel and rapid reduction of effective mobility of Ge MOSFETs.Additionally, it is confirmed that the surface states inside conduction band of Ge can be passivated by annealing the Ge nMOSFETs in atomic deuterium ambient. Besides of surface states, it is also confirmed that the surface state roughness scattering dominates the mobility in high normal field for Ge MOSFETs, similar with the situation in Si MOSFETs. With decreasing the post oxidation temperature, the surface roughness at GeOx/Ge interfaces can be sufficiently reduced without losing the superior electrical passivation much. As a result, around 20% and 25% mobility enhancement can be realized for Ge pMOSFETs and nMOSFETs, respectively, in a high normal field region of N_s=10^<13> cm^<-2> by reducing the post oxidation temperature from 300℃ down to room temperature.

GE通道是SI后CMOS设备最有前途的解决方案之一。移动性增强是限制GE MOSFET的应用的最关键问题。最近，尽管对于高迁移率GE MOSFET已取得了许多进展，但高正常场区域的迁移率仍然很严重，这大大降低了GE MOSFET中的状态电流。尽管很重要，但这种现象的机制尚不清楚。因此，在我们的研究中，系统地研究了导致高正常现场迁移率降解的物理起源。通过评估GE MOSFET中的Hall流动性，发现大量的表面状态存在于GE的价和传统带中，这导致通道中移动载流子浓度显着降低，并且GE MOSFET的有效迁移率迅速降低。在此方面，可以通过GEENEALEALENEAL播出GEENEREAT，从而通过GEEDERIUM播出了GEENEREAT的表面状态。除表面状态外，还可以证实表面状态粗糙度散射在GE MOSFET的高正常场中占主导地位，与Si MOSFET的情况相似。随着氧化后温度的降低，GEOX/GE界面处的表面粗糙度可以充分降低而不会导致上等电钝化。结果，在n_s = 10^<13> cm^<-2>的高正常场区域中，可以分别实现大约20％和25％的迁移率提高，分别通过降低氧化后温度从300℃下降到室温，分别为N_S = 10^<13> cm^<-2>。