Sample stage induced dose and energy nonuniformity in plasma immersion ion implantation of silicon

Fan, Zhengjie; Chu, Paul K.; Chan, Chung; Cheung, N.W.

doi:10.1063/1.121755

Cited by 24 publications

(12 citation statements)

References 13 publications

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“…In many semiconductor PIII applications, the effectiveness of the process hinges on precise control of the substrate temperature in addition to the implantation voltage and ion dose. Accurate and reliable in situ temperature monitoring in separation by plasma implantation of oxygen ͑SPIMOX͒, [6][7][8][9] hydrogen PIII/ion cut, [10][11][12] and elevated-temperature PIII, [13][14][15][16] is crucial to the success. For example, the silicon wafer temperature must be kept at 600°C or higher in SPIMOX, whereas in the hydrogen PIII/ion-cut process, the wafer temperature must remain below 300°C during implantation.…”

Section: Introductionmentioning

confidence: 99%

Direct temperature monitoring for semiconductors in plasma immersion ion implantation

Tian

Chu

2000

Review of Scientific Instruments

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In situ temperature monitoring is extremely important in plasma immersion ion implantation ͑PIII͒ of semiconductors. For instance, the silicon wafer must be heated to 600°C or higher in separation by plasma implantation of oxygen, and in the PIII/ion-cut process, the wafer temperature must remain below 300°C throughout the experiment. In this article, we present a thermocouple-based direct temperature measurement system for planar samples such as silicon wafers. In order to ensure reliable high-voltage operation and overall electrical isolation, the thermocouple assembly and wires are integrated into the sample chuck and feedthrough. Hydrogen plasma immersion ion implantation is performed in silicon to demonstrate the effectiveness and reliability of the device. Our experimental results indicate that instrumental parameters such as implantation voltage, pulse duration, and pulsing frequency affect the sample temperature to a different extent. The measured temperature rise is higher than that predicted by a theoretical model based on the Child-Langmuir law. The discrepancy is attributed to the finite-sample size and the nonplanar, conformal plasma sheath.

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Section: Introductionmentioning

confidence: 99%

Direct temperature monitoring for semiconductors in plasma immersion ion implantation

Tian

Chu

2000

Review of Scientific Instruments

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“…It has been shown that an insulating shroud perturbs the electric field and ion motion, thereby causing lateral variation in the ion implant dose across the wafer. 21 Hence, in spite of some of the attractive features, configuration ͑ii͒ must be used with caution. All in all, with regard to contamination control, configuration ͑iii͒ is the most practical and effective one if an all-silicon chuck cannot be made.…”

Section: Resultsmentioning

confidence: 99%

Metallic contamination in hydrogen plasma immersion ion implantation of silicon

Chu

Zeng

et al. 2001

Journal of Applied Physics

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In plasma immersion ion implantation ͑PIII͒, ions bombard all surfaces inside the PIII vacuum chamber, especially the negatively pulsed biased sample stage and to a lesser extent the interior of the vacuum chamber. As a result, contaminants sputtered from these exposed surfaces can be reimplanted into or adsorb on the silicon wafer. Using particle-in-cell theoretical simulation, we determine the relative ion doses incident on the top, side, and bottom surfaces of three typical sample chuck configurations: ͑i͒ a bare conducting stage with the entire sample platen and high-voltage feedthrough/supporting rod exposed and under a high voltage, ͑ii͒ a stage with only the sample platen exposed to the plasma but the high-voltage feedthrough protected by an insulating quartz shroud, and ͑iii͒ a bare stage with a silicon extension or guard ring to reduce the number of ions bombarding the side and bottom of the sample platen. Our simulation results reveal that the ratio of the incident dose impacting the top of the sample platen to that impacting the side and bottom of the sample stage can be improved to 49% using a guard ring. To corroborate our theoretical results, we experimentally determine the amounts of metallic contaminants on 100 mm silicon wafers implanted using a bare chuck and with a 150 mm silicon wafer inserted between the 100 mm wafer and sample stage to imitate the guard ring. We also discuss the effectiveness of a replaceable all-silicon liner inside the vacuum chamber to address the second source of contamination, that from the interior wall of the vacuum chamber. Our results indicate a significant improvement when an all-silicon liner and silicon guard ring are used simultaneously.

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“…Thus, the implantation uniformity is critically related to ion dose over the surface and the impact angle, a imp . In 1998, Fan et al [5] reported sample stageinduced dose non-uniformity in PIII of silicon. The authors explain the resulted effect by charging of the quartz shroud used to reduce contamination.…”

Section: Introductionmentioning

confidence: 98%

Improvement of the dose uniformity in plasma immersed ion implantation by introducing a vertical biased ring

Stamate¹,

Holtzer²,

Sugai³

2006

Thin Solid Films

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Sample stage induced dose and energy nonuniformity in plasma immersion ion implantation of silicon

Cited by 24 publications

References 13 publications

Direct temperature monitoring for semiconductors in plasma immersion ion implantation

Direct temperature monitoring for semiconductors in plasma immersion ion implantation

Metallic contamination in hydrogen plasma immersion ion implantation of silicon

Improvement of the dose uniformity in plasma immersed ion implantation by introducing a vertical biased ring

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