Browsing by Author "KANG, TK"

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EFFECTS OF POLYSILICON ELECTRON-CYCLOTRON-RESONANCE ETCHING ON ELECTRICAL CHARACTERISTICS OF GATE OXIDES
(1995-05-01)
KANG, TK
;
UENG, SY
;
DAI, BT
;
CHEN, LP
;
CHENG, HC
In spite of the small amount of damage induced by Electron Cyclotron Resonance (ECR) etching, the radiation damage due to vacuum ultraviolet (VUV) photons from the high-density plasma still causes several problems. The leakage currents of the metal-oxide-semiconductor (MOS) capacitors with ECR-etched polysilicon gates are found to be higher than those of the control with wet etching. The leakage mechanism is therefore investigated in detail. The ions and radicals of the ECR plasma can directly attack the peripheral gate oxide and form the surface-damaged layer. In addition, the VUV photons will deeply impact the oxide interior and induce positive charges and interface trap states. ii dilute HF solution can effectively remove the surface damage layer. Annealing at 400 degrees C for 30 min can eliminate completely the positive charges. Furthermore, the SiO2/Si interface trap states are completely removed as the annealing time is raised to 60 min.
EFFECTS OF POSTETCHING TREATMENTS ON ELECTRICAL CHARACTERISTICS OF THERMAL OXIDES ON REACTIVE-ION-ETCHED SILICON SUBSTRATES
(1995-09-01)
CHENG, HC
;
UENG, SY
;
WANG, PW
;
KANG, TK
;
CHAO, TS
Thin oxides thermally grown on the reactive-ion-etched (RIE) silicon substrates in N2O and diluted O-2 ambients have been studied. The RIE will strongly affect the silicon surface microroughness and lead to poor oxides properties. Using the after-treatment-chamber (ATC) process, CF4 addition in the O-2 plasma can further improve the time-zero-to-dielectric-breakdown (TZDB) characteristics of the thin oxides as compared with pure O-2 plasma. This is because CF4 addition in the ATC can remove the damaged silicon layer and smooth the silicon surface since the (O)2 plasma can effectively only strip the polymeric layer. In addition, the N2O-grown oxides can enlarge the process window of the CF4/O-2 ATC treatments with respect to pure oxides.
IMPROVEMENT OF THIN OXIDES THERMALLY GROWN ON THE REACTIVE-ION-ETCHED SILICON SUBSTRATES
(1995-05-01)
UENG, SY
;
WANG, PW
;
KANG, TK
;
CHAO, TS
;
CHEN, WH
Thin oxides thermally grown in reactive-ion-etched (RIE) silicon substrates in N2O and diluted O-2 ambient have been studied. The microroughness of the oxide-silicon interface was investigated using a spectrophotometer, atomic force microscopy (AFM), and cross-sectional high-resolution electron microscopy (HRTEM). The microroughness is strongly dependent on the RIE conditions and the post etching treatments. Furthermore, oxidation-enhanced interface microroughness has been observed. As compared with the pure oxides grown in diluted oxygen, N2O-grown oxides exhibit stronger immunity to RIE-induced damage. N2O oxidation of the etched specimens treated with an after-treatment-chamber (ATC) process result in the best electrical properties.