脉冲流量PECVD瞬态生长机理研究

Passsivation is one of the most important process for high efficient crystalline silicon solar cells. Two methods, Plasma enhanced chemical vapor deposition (PECVD) and atomic layer deposition (ALD), are always used to deposition passivation films. The deposition rate of PECVD based on island grown mechanism is high, while the film properties are not good enough; ALD, based on self-limiting growth, is an attractive technique due to its potential to deliver high quality passvation films, but the deposition rate is so poor. It is a challenge to passivate crystalline silicon solar cell with good quality and high velocity. Pulsed flow PECVD is a new deposition technology with precursor injection pulses. The deposition process is governed by film growth after the precursor pulses and subsequently, densification of the deposited layer in the remainder of the interval between the precursor pulses. The transient change of component of plasma lead to the variation of film properties among densificaiton stage, and the deposition process varies from island growth to layer-by-layer growth process. But the transient densificaiton mechanism is not clear and needs to be studied. The aim of this project is to investigate the transient densificaition mechanism theoretically and experimently, create the grown modle of plused-flow PECVD, and deliver high-quality passivation films with excellent deposition rate by plused-flow PECVD.

钝化是高效晶硅太阳能电池的核心工艺之一。PECVD和ALD是两种常被用于生长钝化薄膜的技术。基于岛式连续生长PECVD技术沉积速度快，但薄膜质量差；基于自限制生长机理的ALD技术沉积薄膜质量高，但层层式沉积速度慢。如何实现高质量钝化薄膜快速生长成为一个难题。脉冲流量PECVD是一种基于脉冲流量前驱体的新沉积技术，每个沉积周期由脉冲前驱体通入时的薄膜连续生长过程和脉冲前驱体停止通入后已沉积薄膜修复过程组成。其中，前驱体停止通入后等离子体组分的瞬态变化导致沉积薄膜缺陷和薄膜质量的变化，薄膜生长过程也由类传统PECVD岛状生长过渡到类ALD低缺陷生长，但瞬态修复机理尚不清楚。本项目皆在研究脉冲流量PECVD瞬态修复机理，建立脉冲流量PECVD瞬态生长全过程模型，可控地快速沉积高质量钝化薄膜。

钝化是高效晶硅太阳能电池的核心工艺之一。PECVD和ALD是两种常被用于生长钝化薄膜的技术。基于岛式连续生长PECVD技术沉积速度快，但薄膜质量差；基于自限制生长机理的ALD技术沉积薄膜质量高，但层层式沉积速度慢。如何实现高质量钝化薄膜快速生长成为一个难题。脉冲流量PECVD是一种基于脉冲流量前驱体的新沉积技术，每个沉积周期由脉冲前驱体通入时的薄膜连续生长过程和脉冲前驱体停止通入后已沉积薄膜修复过程组成。其中，前驱体停止通入后等离子体组分的瞬态变化导致沉积薄膜缺陷和薄膜质量的变化，薄膜生长过程也由类传统PECVD岛状生长过渡到类ALD低缺陷生长，但瞬态修复机理尚不清楚。本项目皆在研究脉冲流量PECVD瞬态修复机理，建立脉冲流量PECVD瞬态生长全过程模型，可控地快速沉积高质量钝化薄膜。