Browsing by Author "Liaw, MC"

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Mechanism of nitrogen coimplant for suppressing boron penetration in p(+)-polycrystalline silicon gate of p metal-oxide semiconductor field effect transistor
(1996-09-16)
Chao, TS
;
Liaw, MC
;
Chu, CH
;
Chang, CY
;
Chien, CH
The mechanism of the nitrogen co-implant to suppress the boron penetration in p(+)-polycrystalline silicon gate has been investigated. The nitrogen coimplant with the BF, combines with the boron to form a B-N complex which results in a retardation of boron diffusion. It is found that metal-oxide-silicon capacitors with nitrogen implantation show improved electrical properties. (C) 1996 American Institute of Physics.
Mechanism of nitrogen coimplant for suppressing boron penetration in p(+)-polycrystalline silicon gate of p metal-oxide semiconductor field effect transistor
(1996-09-16)
Chao, TS
;
Liaw, MC
;
Chu, CH
;
Chang, CY
;
Chien, CH
The mechanism of the nitrogen co-implant to suppress the boron penetration in p(+)-polycrystalline silicon gate has been investigated. The nitrogen coimplant with the BF, combines with the boron to form a B-N complex which results in a retardation of boron diffusion. It is found that metal-oxide-silicon capacitors with nitrogen implantation show improved electrical properties. (C) 1996 American Institute of Physics.
Novel cleaning solutions for polysilicon film post chemical mechanical polishing
(2000-07-01)
Pan, TM
;
Lei, TF
;
Chen, CC
;
Chao, TS
;
Liaw, MC
Novel cleaning solutions were developed for post-CMP process, surfactant tetra methyl ammonium hydroxide (TMAH) and/or chelating agent ethylene diamine tetra acetic acid (EDTA) were added into the diluted ammonium hydroxide (NH4OH+H2O) alkaline aqueous solution to enhance removal of metallic and organic contamination, From the experimental result, it is found that the particle and metal removal efficiency and the electrical characteristics are significantly improved for post-CMP cleaning.
One-step cleaning solution to replace the conventional RCA two-step cleaning recipe for pregate oxide cleaning
(2001-06-01)
Pan, TM
;
Lei, TF
;
Chao, TS
;
Liaw, MC
;
Ko, FH
This work proposes an advanced wet chemical one-step cleaning process which omits the hydrochloric acid/hydrogen peroxide/water mixture (HPM) step in RCA. A novel one-step cleaning solution had been developed for pregate oxide cleaning to replace the conventional RCA two-step cleaning recipe, which used ammonia/hydrogen peroxide (or SC-1) and HPM (or SC-2) step. Tetramethylammonium hydroxide (TMAH) and ethylenediaminetetraacetic acid (EDTA) were added into the RCA SC-1 cleaning solution to enhance cleaning efficiency. From the experimental results, the particles and metallic contamination on the bare Si wafer surface could be removed significantly by applying this one-step cleaning solution. The effectiveness of various cleaning recipes and their interaction mechanism with silicon surfaces were studied. The surface adsorption and double layer models could explain the surface behavior of TMAH solutions. Based on the model, the particle, surface roughness and metallic contaminants can be realized. It was observed that the electrical properties of metal oxide semiconductor capacitors after cleaning with this novel solution were better than those after the conventional RCA cleaning. Besides, the cleaning method combining NH4OH, tetramethylammonium hydroxide, ethylenediaminetetraacetic acid, and H2O2, at 80 degreesC for 3 min showed high performance on particle removal, metal cleaning, surface smoothness, and electrical properties. Hence, this one-step cleaning process is very promising for future large sized silicon wafer cleaning due to the advantages of time-saving, low cost, and high performance. (C) 2001 The Electrochemical Society.
Optimum conditions for novel one-step cleaning method for pre-gate oxide cleaning using robust design methodology
(2000-10-01)
Pan, TM
;
Lei, TF
;
Chao, TS
;
Liaw, MC
;
Lu, CP
A novel one-step cleaning method has been developed for pre-gate-oxide cleaning to replace the conventional RCA two-step cleaning process. Tetramethyl ammonium hydroxide (TMAH) and ethylenediamine tetraacetic acid (EDTA) are added into the RCA SC-1 cleaning solution to enhance cleaning efficiency. We adapt a robust design methodology (Genichi Taguchi method) to analyze the results of our experiments. Using this novel method, it is found that the optimum conditions are A(1)B(2)C(1)D(1) (A(1): TMAH : NH4OH = 1 : 50, B-2: EDTA concentration is 100 ppm, C-1: cleaning time is 5 min, and D-1: cleaning temperature is 60 degreesC). This novel one-step cleaning method is very promising for future large-sized silicon wafer cleaning processes because it has the advantages of reduced processing time and temperature, cost reduction due to reduced chemical usage and improved performance.
Performance evaluation of cleaning solutions enhanced with tetraalkylammonium hydroxide substituents for post-CMP cleaning on poly-Si film
(2002-06-01)
Pan, TM
;
Lei, TF
;
Ko, FH
;
Chao, TS
;
Liaw, MC
The cleaning solutions augmented with tetraalkylammonium hydroxides (TAAHs) with various chain-lengths of hydrocarbon substituents were developed for post-poly-Si chemical mechanical polishing (CMP) cleaning. The cleaning performance with respect to particle, organic, and metal removal as well as surface roughness was evaluated for a series of 3% NH4H solutions dosed with 0.26 M of a TAAH and 100 ppm of ethylenediaminetetraacetic acid (EDTA). The experimental results demonstrated that the cleaning solutions enhanced with these surfactants (TAAH) and a chelating agent (EDTA) achieved significantly better removal efficiencies of particle and metal impurities than the control solution containing 3% NH4OH only. A conceptual model involving surface adsorption and double-layer formation was used to postulate the aqueous-phase surface interactions between the tetraalkylammonium cations and the poly-Si surface, and to explain the removal mechanisms of particle and metal impurities from the surface. The improved electrical properties (current density-electric field and charge-to-breakdown characteristics) of the post-CMP capacitor after cleaning further demonstrated the reliability and feasibility of the proposed cleaning recipes. (C) 2002 The Electrochemical Society.
Suppression of boron penetration in P+-poly-Si gate metal-oxide-semiconductor transistor using nitrogen implantation
(1997-03-01)
Chao, TS
;
Chien, CH
;
Hao, CP
;
Liaw, MC
;
Chu, CH
The mechanism and the optimization of nitrogen implantation for suppression the boron penetration in p(+)-poly-Si gate metal-oxide-semiconductor capacitor is reported. This nitrogen co-implantation process exhibits a good suppression of boron penetration and a better electrical characteristic than that of control sample. It was found that nitrogen combines with the boron to form a B-N complex, retarding the penetration of boron itself, was identified by XPS measurements. The optimum nitrogen dosage is also found in this study.