Browsing by Author "Yeh, Chi-Ruei"

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Channel Film Thickness Effect of Low-Temperature Polycrystalline-Silicon Thin-Film Transistors
(2011-04-01)
Ma, William Cheng-Yu
;
Chiang, Tsung-Yu
;
Yeh, Chi-Ruei
;
Chao, Tien-Sheng
;
Lei, Tan-Fu
In this paper, the channel-film-thickness effect of low-temperature polycrystalline-Si thin-film transistors (LTPS-TFTs) is investigated. Greater channel film thickness can provide a higher field-effect mobility mu FE, rising from 14.33 to 22.33 cm(2)/V . s, as the channel film thickness increases from 55 to 120 nm, due to grain-size effect. In addition, varying the channel film thickness of LTPS-TFTs results in different junction leakage current due to the source/drain (S/D) junction area effect. Moreover, the S/D series resistance also significantly increases when the channel film thickness is reduced from 120 to 35 nm, leading to poor field-effect mobility mu FE and driving current. Consequently, the optimum channel film thickness for active-matrix liquid-crystal displays may be identified.
Characteristics of SONOS-Type Flash Memory With In Situ Embedded Silicon Nanocrystals
(2010-08-01)
Chiang, Tsung-Yu
;
Wu, Yi-Hong
;
Ma, William Cheng-Yu
;
Kuo, Po-Yi
;
Wang, Kuan-Ti
In this paper, silicon-oxide-nitride-oxide-semiconductor (SONOS) devices with embedded silicon nanocrystals (Si-NCs) in silicon nitride using in situ method with multilevel and 2-b/cell operation have been successfully demonstrated. The proposed in situ Si-NC deposition method exhibits the advantages of low cost, simplicity, and compatibility with modern IC processes. SONOS memories with embedded Si-NCs exhibit a significantly improved performance with a large memory window (> 5.5 V), low operating voltage (P/E voltage: V(g) = 6 V, V(d) = 7 V and V(g) = -7 V, V(d) = 10 V, respectively), greater tolerable gate and drain disturbance (V(t) shift < 0.2 V), negligible second-bit effect, high P/E speed (after programming time = 10 mu s with a 2-V shift of V(t) under V(g) = V(d) = 6 V operation), good retention time (> 10(8) s for 13% charge loss), and excellent endurance performance (after 10(4) P/E cycles with a memory window of 3 V).
Electrical Characteristics of High Performance SPC and MILC p-Channel LTPS-TFT with High-kappa Gate Dielectric
(2009)
Ma, Ming-Wen
;
Chiang, Tsung-Yu
;
Yeh, Chi-Ruei
;
Chao, Tien-Sheng
;
Lei, Tan-Fu
In this article, high performance p-channel, low temperature polysilicon thin-film transistors (LTPS-TFTs) are fabricated by using HfO(2) gate dielectric and two crystallization methods, solid phase crystallization (SPC) and metal-induced lateral crystallization (MILC) are compared. High field-effect mobility mu(FE) 114 and 215 cm(2)/V s), ultralow subthreshold swing (SS similar to 145 and 107 mV/decade), and low threshold voltage (V(th) similar to -1.05 and -0.75 V) are derived from SPC- and MILC-TFTs with HfO(2) gate dielectric, respectively. These excellent electrical characteristics are due to low trap states and much higher gate capacitance density with equivalent oxide thickness similar to 12.3 nm, resulting in lower operation voltage within 2 V of LTPS-TFT without any passivation method. The comparison of SPC and MILC p-channel LTPS-TFTs with HfO(2) gate dielectric is demonstrated. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3177277] All rights reserved.
MILC-TFT With High-kappa Dielectrics for One-Time-Programmable Memory Application
(2009-09-01)
Chiang, Tsung-Yu
;
Ma, Ming-Wen
;
Wu, Yi-Hong
;
Kuo, Po-Yi
;
Wang, Kuan-Ti
In this letter, for the first time, one-time-programmable (OTP) memory fabricated on the low-temperature poly-Si p-cbannel thin-film transistor (TFT) with metal-induced lateral-crystallization channel layer and high-kappa dielectrics is demonstrated. The state of this OTP memory can be identified by the scheme of gate-induced drain leakage current measurement. The OTP-TFT memory has good electrical characteristics in terms of low threshold voltage V(th) similar to -0.78 V, excellent subthreshold swing similar to 105 mV/dec, low operation voltage, faster programming speeds, and excellent reliability characteristics.