Conclusions

We have developed an optimized deposition condition for sol-gel ZrZnO semiconductor film and succeeded to fabricate a ZrZnO-based transparent thin film transistor with bottom-gate structure. The optimal conditions for depositing the ZrZnO film by spin coater are at room temperature and deposit two layers, each layer is baked on the hotplate at 300°C for 60 minutes. After film deposition, devices are taken one curing step under oxygen ambience at 350°C for 60 minutes. With the development of wet etchants, active regions can be patterned accurately.

We solve the time dependent behaviors of devices and light illumination effect by adding post annealing treatment under nitrogen ambience at 350°C to complete device fabrication. Besides, the oxygen adsorption theory successfully explained the mechanisms of light illumination effect and oxygen pressure effect. ZnO, ZTO and IZO are also discussed to replace the active channel layer in this thesis. Devices with IZO active layer have the best performance, which can compete with traditional a-si TFTs. We also make some measurements to test electrical stability of devices, such as light illumination, oxygen pressure, and bias stress. At last, we successfully demonstrated sol-gel derived ZnO and ZrZnO and IZO based TFTs on glass substrate by spin-on deposition at low temperature. For large area flat-panel display fabrication in the future, the chemical solution deposition process provides a low cost and more efficient way for depositing devices than vacuum deposition techniques.

Reference

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Chapter4

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Fig1-1 The wurtzite lattice structure of zinc oxide: small circles represent

zinc atoms, the large circles are oxygen atoms.

Fig2-1 The device structure of thin film transistor

V_G(V)

Fig2-2 Transfer characteristics of ZrZnO TFTs that are fabricated by

“Standard Manufacturing Processes”

Fig2-3 Time dependent transfer characteristics of ZrZnO TFTs that are

fabricated by “Standard Manufacturing Processes”

Fig3-1 Lennard-Jones Model of physisorption and chemisorption; (a)

phtsisorption of a molecule, (b) chemisorption, where at d=∞, enough energy has been introduced to dissociate the molecule

V_G-I_D (V_D=21V)

V_G(V)

-60 -40 -20 0 20 40 60 80

I_D(A)

10^-13 10^-12 10^-11 10^-10 10^-9 10^-8 10^-7 10^-6 10^-5

10 mins 30 mins 60 mins STD

Fig3-2 Transfer characteristics of ZrZnO TFTs that are annealed under

oxygen ambience with various time

V_G-I_D (V_D=21V)

Fig3-3 Time dependent transfer characteristics of ZrZnO TFTs that are

annealed under oxygen ambience for 60 minutes

V_G-I_D (V_D=21V)

Fig3-4 Transfer characteristics of ZrZnO TFTs that are annealed in

V_G(V)

Fig3-5 Time dependent transfer characteristics of ZrZnO TFTs that are

annealed in vacuum for 10minutes

V_G-I_D (V_D=21V)

Fig3-6 Transfer characteristics of ZrZnO TFTs that are annealed under

nitrogen ambience with various time

V_G(V)

Fig3-7 Time independent transfer characteristics of ZrZnO TFTs that are

annealed under nitrogen ambience for 10 minutes

V_G-I_D (V_D=21V)

Fig3-8 Transfer characteristics of ZrZnO TFTs with various baking time

V_G-I_D (V_D=21V)

Fig3-9 Transfer characteristics of ZrZnO TFTs which suffer seriously

Drain Induced Barrier Lowering effect (DIBL)

V_G-I_D (V_D=21V)

Fig3-10 Transfer characteristics of ZrZnO TFTs with HMDS coating

baked for various time

V_G-I_D (V_D=21V)

Fig3-11 Transfer characteristics of ZrZnO TFTs that are baked for 10

minutes with or without HMDS coating

V_G-I_D (V_D=21V)

Fig3-12 Transfer characteristics of ZrZnO TFTs that are baked for 30

minutes with or without HMDS coating

V_G-I_D (V_D=21V)

Fig3-13 Transfer characteristics of ZrZnO TFTs that are baked for 60

minutes with or without HMDS coating

u/u₀ vs Baking Tim e

Mobility Changing Ratio (u/u o)

u_o: Before HMDS coating u : After HM DS coating

10m ins 30mins 60mins

Fig3-14 Mobility changing ratio with various baking time

V_G-I_D (V_D=21V)

Fig3-15 Transfer characteristics of ZrZnO TFTs with different numbers

of active layers

Fig3-16 Transfer characteristics of ZrZnO TFTs that are treated with RTA

under NH3 ambience

V_G-I_D (V_D=21V)

Fig3-17 Transfer characteristics of ZrZnO TFTs that are treated with RTA

under Ar ambience

Fig3-18 Transfer characteristics of ZrZnO TFTs before and after SiOx

passivation

V_G-I_D of SiN_x Passivation (V_D=21V)

Fig3-19 Transfer characteristics of ZrZnO TFTs before and after SiNx

passivation

Fig3-20 Transfer characteristics of ZrZnO TFTs before and after PC403

passivation

V_G-I_D of ZrZnO TFT

Fig3-21 Transfer characteristics of ZrZnO TFTs that are fabricated by the

optimal conditions

V_D-I_D of ZrZnO TFT

V_G-I_D of ZnO TFT

Fig3-23 Transfer characteristics of ZnO TFTs that are fabricated by the

optimal conditions acquired from ZrZnO TFTs

V_D-I_D of ZnO TFT

Fig3-24 I

D-VD of ZnO TFTs that are fabricated by the optimal conditions acquired from ZrZnO TFTs

V_G-I_D of ZTO TFT

Fig3-25 Transfer characteristics of ZTO TFTs

V_D-I_D of ZTO TFT

V_G-I_D of IZO TFT

Fig3-27 Transfer characteristics of IZO TFTs

V_D-I_D of IZO TFT

V_G-I_D (V_D=21V)

Fig4-1 Transfer characteristics of ZrZnO TFTs with light illumination

and hold for 15 minute in dark environment

V_G-I_D (V_D=21V)

Fig4-2 Transfer characteristics of ZrZnO TFTs that are annealed under

nitrogen with light illumination and hold for 1 minute in dark environment

Fig4-3 Physical model of oxygen effect on the conductance of ZnO film

and the interaction with light

V_G-I_D (V_D=21V)

V_G(V)

-40 -20 0 20 40 60

I_D(A)

10^-14 10^-13 10^-12 10^-11 10^-10 10^-9 10^-8 10^-7 10^-6

10^-5 _{1 torr}

10 torr 100 torr 760 torr

Fig4-4 Transfer characteristics of ZTO TFTs that are measured under

different oxygen pressure

Fig4-5 Transfer characteristics of IGZO TFTs that are measured under

different oxygen pressure

V_G-I_D (V_D=21V)

V_G(V)

-60 -40 -20 0 20 40 60 80

10^-14 10^-13 10^-12 10^-11 10^-10 10^-9 10^-8 10^-7 10^-6 10^-5 10^-4 10^-3

I_D(A)

1 torr 10 torr 100 torr 760 torr

Fig4-6 Transfer characteristics of ZTO TFTs with light illumination that

are measured under different oxygen pressure

V_G-I_D (V_D=1V)

Fig4-7 Transfer characteristics of ZrZnO TFTs under gate bias stress for

1000s and after relax for 1000s at room pressure

V_G-I_D (V_D=1V)

Fig4-8 Transfer characteristics of ZrZnO TFTs under gate bias stress for

1000s and after relax for 1000s in vacuum

Table2-1 Experiment flow of in this experiment

Table2-2 Experiment flow of sol-gel precursor preparation

Table2-3 Experiment flow of various ambience and treatment time

Table2-4 Experiment flow of various numbers of active channel layer

Table2-5 Experiment flow of various baking time and with or w/o HMDS

coating

Table2-6 Experiment flow of various RTA and passivation processes

Table3-1 The characteristics of physisorption and chemisorption

Table3-2 The electrical parameters of various TFTs

Table4-1 Experiment flow of devices under light illumination

Table4-2 Experiment flow of devices measured under different oxygen

pressure

Table4-3 Experiment flow of devices measured under gate bias stress

簡 歷

姓 名：郭 豫 杰 ( Yu-Chieh Kuo )

性 別：男

出生年月日：民國 73 年 08 月 26 日

住 址：台北市光復北路103巷36號3樓

學 歷：

國立清華大學工業工程與工程管理學系學士 (91.9-95.6) 國立交通大學光電工程學系顯示科技研究所碩士 (95.9-97.6)

碩士論文題目:

溶膠凝膠金屬氧化物薄膜電晶體之研究

Investigation on Sol-Gel Derived Metal Oxide Semiconductor Thin Film Transistors

在文檔中 溶膠凝膠金屬氧化物薄膜電晶體之研究 (頁 40-71)