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Single Crystal Silicon Growth Method And Prepared Single Crystal Silicon Ingot And Process
- Jan 05, 2019 -

The present invention relates to a method of growing silicon crystals, and more particularly to a method of growing single crystal silicon.

Background technique:

In the single crystal silicon growth process of the Czochralski method (hereinafter sometimes referred to as the Czochralski method), due to the melting of the quartz crucible, part of the oxygen enters the single crystal silicon, and these oxygen mainly exist in the silicon lattice. The gap position. Precipitation occurs when the concentration of interstitial oxygen exceeds the solubility of oxygen in silicon, thereby forming a common oxygen precipitation defect in single crystal silicon, which in turn causes damage to integrated circuit devices.

An intrinsic gettering technique, in which a high-density oxygen precipitate is formed in a silicon wafer by a certain procedure, and a defect-free clean region of a certain depth can be formed on the surface of the silicon wafer, and the clean region can be applied. Manufacturing equipment. However, with the development of very large scale integrated circuits (ULSI), the feature size is getting smaller and smaller, and it is necessary to reduce the oxygen concentration in the single crystal silicon to avoid formation of defects in the active region of the device. In addition, since the thermal budget of the integrated circuit process is significantly reduced, the conditions for forming oxygen precipitates in the silicon wafer cannot be sufficiently satisfied, thereby affecting the effect of endoplasmic absorption.

The above problem can be solved by doping nitrogen in Czochralski silicon. Nitrogen can promote the precipitation of oxygen in the Czochralski silicon, thereby enhancing the endoplasmic absorption effect. Nitrogen doping also increases the mechanical strength of the silicon wafer and suppresses void defects. The distribution of oxygen precipitation was studied by infrared light scattering tomography (IR-LST) and scanning infrared microscopy (SIRM). The results show that after a high-temperature annealing of 300mm nitrogen-doped Czochralski silicon wafer with suitable nitrogen concentration A high-density oxygen precipitate can be formed and a clean region of a certain width is formed at the near surface of the silicon wafer; moreover, as the nitrogen concentration increases, the radial distribution of oxygen precipitates in the silicon wafer is more uniform.

The industry generally uses solid phase nitrogen doping, such as silicon nitride (Si3N4) powder, for single crystal silicon nitrogen doping, this method can control the nitrogen doping concentration more accurately, but high purity silicon nitride (Si3N4) powder is difficult to obtain, Moreover, Si3N4 particles are often left to be difficult to melt, and it is difficult to achieve dislocation-free growth of single crystal silicon. The industry also adopts gas phase nitrogen doping, which is introduced into the high-purity nitrogen or nitrogen/argon mixed gas after the seed crystal is welded, and the nitrogen doping concentration is controlled by the nitrogen introduction time. The gas phase nitrogen doping is achieved by reacting nitrogen with a silicon melt to achieve nitrogen doping, and the purity is high, and the silicon nitride formed by the reaction is less likely to be granulated. However, since the reaction is completely dependent on heat convection, the process is difficult to control and the nitrogen doping concentration is difficult. Less uniform. Accordingly, there is still a need for a method of manufacturing single crystal silicon.

On the other hand, the use of hydrogen to form a passivation layer has been widely known and commonly used in the field of semiconductor device fabrication. In the hydrogen passivation process, the influence of defects on the semiconductor device can be removed. For example, such defects are described as active components at the center of a composite or semiconductor device. These centers are caused by dangling bonds that are capable of removing charge carriers or introducing unnecessary charge carriers, depending in part on the bias voltage. The dangling bonds occur mainly at the interface of the surface or device, and they can also occur at vacancies, micropores, etc., which are also associated with impurities.

In the field of semiconductor manufacturing, there is also a problem that device performance is degraded by hot carriers. This problem is especially important in small size devices and high voltage devices. When a high voltage device is used, carriers within the channel have greater energy to penetrate into the insulating layer, thereby degrading the performance of the device.