Determination of Oxygen Diffusion Coefficient in Silicon Substrate During Dry Oxygen Diffusion

Abstract

The invention provides a method for determining the diffusion coefficient of oxygen in a silicon substrate during the dry oxygen diffusion process to obtain the film thickness of silicon dioxide. The present invention does not continue to conduct experiments until the film thickness of silicon dioxide reaches the required method. Instead, by simulating the process of dry oxygen diffusing to a given thickness in a silicon substrate at a given temperature, the relationship between the diffusion coefficient and temperature is obtained, and then the diffusion coefficient at any temperature is calculated. According to the calculated diffusion coefficient, the diffusion of dry oxygen in the silicon substrate under given conditions can be simulated, and the SiO 2 Adjust the process parameters in a small range, and find out the best process parameters, reduce the experimental range, improve the efficiency of furnace tube grid oxide program establishment, and reduce the number of experiments.

Description

technical field [0001] The invention relates to the field of microelectronics, in particular to a method for determining the diffusion coefficient of oxygen in a silicon substrate during the process of dry oxygen diffusion. Background technique [0002] With the rapid development of the microelectronics industry and VLSI, the application of MOS devices is deepening, and its size is also decreasing. At present, the furnace tube grid oxide program is mostly established by the orthogonal experiment method, that is, the experiment is carried out continuously until the film thickness meets the requirements, and the program is established according to the process parameters at this time. This method has the following disadvantages: First, the gate oxide growth is a diffusion process, and the film thickness does not always increase linearly with time, so it is difficult to accurately adjust the diffusion time, so this method requires multiple experiments; secondly, in addition to t...

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Problems solved by technology

This method has the following disadvantages: First, the gate oxide growth is a diffusion process, and the film thickness does not always increase linearly with time, so it is difficult to accurately adjust the diffusion time, so this method requires multiple experiments; secondly, in addition to the oxidation step, the gate oxide growth There is often a subsequent heat treatment process. During the heat treatment process, the thickness of the gate oxide will further increase, which increases the difficulty of the design of the experimental plan and reduces the efficiency of the experiment. In addition, this method produces a gate oxide with a dense structure, but the oxidation speed is slow. The oxidation time is long, and at the same time, the furnace tube process undergoes a large amount of heating and cooling time, resulting in a longer cycle for each experiment, which makes it take a long time for the equipment and a high thermal budget

[0004] Although the above method is simple, it needs to know the oxygen diffusion coefficient at the current diffusion temperature

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