Gary E. Miner

Advances in Rtp Temperature Measurement and Control

This paper reviews work to develop and improve the temperature measurement and control technology of a commercial rapid thermal processing (RTP) system. A description of the main features of this system is given, which includes a concentric multi-zone lamp heating source, multi-point temperature measurement system and real time wafer temperature control. Innovations in RTP optical thermometry are described which resulted in improved low temperature performance, a real time spectral emissivity measurement tool which enables emissivity independent temperature measurement and an improved temperature calibration capability. The multi-input multi-output (MIMO) optimal wafer temperature control methodology is discussed. Process results demonstrating an equivalent process temperature performance of 4°C, 3-sigma, all-points-all-wafers will be presented.

Device performance of in situ steam generated gate dielectric nitrided by remote plasma nitridation

In situ steam generated (ISSG) oxides have recently attracted interest for use as gate dielectrics because of their demonstrated reliability improvement over oxides formed by dry oxidation. [G. Minor, G. Xing, H. S. Joo, E. Sanchez, Y. Yokota, C. Chen, D. Lopes, and A. Balakrishna, Electrochem. Soc. Symp. Proc. 99-10, 3 (1999); T. Y. Luo, H. N. Al-Shareef, G. A. Brown, M. Laughery, V. Watt, A. Karamcheti, M. D. Jackson, and H. R. Huff, Proc. SPIE 4181, 220 (2000).] We show in this letter that nitridation of ISSG oxide using a remote plasma decreases the gate leakage current of ISSG oxide by an order of magnitude without significantly degrading transistor performance. In particular, it is shown that the peak normalized transconductance of n-channel devices with an ISSG oxide gate dielectric decreases by only 4% and the normalized drive current by only 3% after remote plasma nitridation (RPN). In addition, it is shown that the reliability of the ISSG oxide exhibits only a small degradation after RPN. These ...

Trends in gate stack engineering

MOSFET scaling requires an increase in the dielectric capacitance and hence a decrease in the dielectric electrical thickness. In this paper, we review the scaling trends for the gate dielectric and the gate electrode as the industry faces the challenges of introducing new materials into production.

Nitrogen Profile Engineering in Thin Gate Oxides

In order to prevent boron penetration in PMOS transistors without degrading channel mobility, it is necessary to engineer the distribution of nitrogen introduced into the gate oxide. We have investigated methods of engineering this distribution using nitric oxide (NO) gas in an RTP system to thermally nitride ultra-thin gate oxides. In one approach, the gate oxide is simultaneously grown and nitrided in a mixture of nitric oxide and oxygen. For a 40 A film, SIMS depth profiling shows that this process moves the nitrogen peak into the bulk of the oxide away from the oxide silicon interface. In another approach, an 11 A chemical oxide produced by a standard pre-furnace wet clean is nitrided in NO at 800 deg. C. This film is subsequently reoxidized in either oxygen or steam. For an 1100 deg. C., 120 sec RTP reoxidation in oxygen, the final film thickness is 41 A. The nitrogen has a peak concentration of 5 at. % and the peak is located in the oxide 25 Afrom the oxide/silicon interface. Ramped voltage breakdown testing was carried out on MOS capacitors built using reoxidized NO nitrided films. They have breakdown characteristics that are equivalent to conventional furnace grown oxides. These films show considerable promise as gate dielectrics for CMOS technologies at geometries of 0.25um and below.

Uniform Ultra-Thin Oxides Grown by Rapid Thermal Oxidation of Silicon in N 2 O Ambient

In this paper, we report the study of rapid thermal oxidation of silicon in N 2 O ambient using the Applied Materials RTP Centura rapid thermal processor, and N 2 O oxide thickness and compositional uniformities with respect to gas flow rate and wafer rotation speed as well as other process parameters. It was found that N 2 O oxide uniformity is strongly dependent on gas flow rate and wafer rotation speed in addition to process pressure. With optimized setting of the process parameters, excellent oxidation uniformities (one sigma 2 O ambient. Nitrogen concentrations of such uniform oxides grown at 1050°C atmospheric pressure N 2 O oxidation processes were 1.7% for a 40A oxide and 2.5% for a 60A oxide, respectively, as characterized by SIMS analysis.

Remote Plasma Nitridation of In-Situ Steam Generated (ISSG) Oxide

Electrical performance of in-situ steam generated (ISSG) oxide nitrided using remote plasma nitridation (RPN) has been evaluated. An equivalent oxide thickness (EOT) of 1.6 nm with gate leakage current around 5×10 −3 A/cm 2 (at −1.5V) has been achieved. The leakage current of remote plasma nitrided ISSG oxide is lower than that of ISSG only, where more than one order of magnitude leakage current reduction (at the same EOT) has been achieved for some RPN conditions. Moreover, it is observed that the extent to which the RPN process conditions modify device parameters such as EOT, flatband voltage (V FB ), and time-to-breakdown (t bd ) increases with decreasing ISSG thickness. The thinner ISSG oxides appear to be more susceptible to plasma damage and accumulation of positively charged nitrogen atoms at the oxide/Si interface. Therefore, RPN processes that use lower temperature and shorter time are preferred for very thin oxides. The nitrogen content and profile in the samples evaluated using SIMS analysis, indicate that RPN offers higher nitrogen content and better nitrogen profile compared to conventional nitrogen incorporation methods such as NO annealing [1].

Ultrathin NO/N 2 O Oxynitride Dielectric For Advanced Flash Memory Application: Single Wafer and Batch Technology

In this paper a systematic investigation of nitrided oxides obtained by Rapid Thermal Oxidation/Nitridation (RTO/RTN) in AMAT Centura System is reported. Two different aspects were considered: first the comparison between single wafers and batch technology, second the different possible oxide architecture achievable with RTO/RTN system (i.e. RTO + RTN, RTN + RTO, RTN + RTO + RTN). Both morphological and patterned wafers were processed. Physical and chemical characterizations were carried out by means of SIMS, XPS, ELYMAT, AFM and Etching Rate studies. Morphological results were then correlated to electrical data obtained on MOS capacitors. The film obtained performing a NO RTN nitridation of the native oxide followed by a ISSG (In Situ Steam Generation) oxidation exhibited very promising electrical properties that made it an appealing candidate as gate dielectric in CMOS and Flash memories applications.