Mobility Enhancement of Polycrystalline MgZnO/ZnO Thin Film Layers With Modulation Doping and Polarization Effects

Author

Huang, Chih-I ; Chin, Huai-An ; Wu, Yuh-Renn ; Cheng, I-Chun ; Chen, Jian Z. ; Chiu, Kuo-Chuang ; Lin, Tzer-Shen

Author_Institution

Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei, Taiwan

Volume

57

Issue

3

fYear

2010

fDate

3/1/2010 12:00:00 AM

Firstpage

696

Lastpage

703

Abstract

ZnO has shown great promise for application in optoelectronic devices, in which the modulation of conductivity is crucial to device performance. In this paper, we have applied the Monte Carlo method to analyze the mobility of single-crystalline and polycrystalline MgZnO/ZnO heterostructure thin film layers. The effects of grain boundary scattering and ionized impurity scattering, as well as phonon scattering, are considered. Our studies show that, with careful design of modulation doping that considers the effects of spontaneous and piezoelectric polarization, the grain boundary potential can be suppressed to improve the mobility of the ZnO layer by at least one order of magnitude. Simulation results are also confirmed by our experimental work, which shows that the polarization effect does play an important role in attracting carriers and increasing the mobility.

Keywords

II-VI semiconductors; Monte Carlo methods; carrier mobility; dielectric polarisation; grain boundaries; impurity scattering; manganese compounds; semiconductor doping; semiconductor thin films; thin film transistors; wide band gap semiconductors; zinc compounds; MgZnO-ZnO; Monte Carlo method; conductivity modulation; grain boundary potential; grain boundary scattering effect; ionized impurity scattering effect; mobility enhancement; modulation doping; optoelectronic devices; phonon scattering effect; polarization effect; polycrystalline heterostructure thin film layer; single-crystalline heterostructure thin film layer; spontaneous piezoelectric polarization; Conductivity; Epitaxial layers; Grain boundaries; Impurities; Optoelectronic devices; Piezoelectric films; Piezoelectric polarization; Scattering; Transistors; Zinc oxide; Mobility; Monte Carlo; ZnO; modulation doping; polycrystalline; thin-film transistor (TFT);

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2009.2039527

Filename

5398975