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用四探针测量薄层电导方法及阳极氧化去层技术,测定了磷在硅中扩散的具体分布,在恒表面浓度下,它们偏离余误差函数分布。如认为这是由于扩散系数是杂质浓度的函数,实验得到了当杂质浓度大于10~(19)原子/厘米~3时,扩散系数随杂质浓度增加而增大的强烈依赖关系。 用同样方法测定了磷通过二氧化硅层后在硅中扩散的具体分布,研究了这些杂质分布的特性,实验表明,不同厚度的氧化层在1300℃高温下仍具有掩蔽效应,在完全掩蔽失效时间附近,杂质分布的共同特点是表面浓度较低(～10~(17)原子/厘米~3)、结较浅(～1微米)。对不同厚度的氧化层,经过足够的时间后,硅中表面浓度不受氧化层厚度的影响,而只由扩散源的蒸气压决定。磷通过氧化层后扩散的具体分布情况还与扩散源的性质、条件等密切相关。扩散过程中观察到的氧化层厚度增长有可能影响表面附近杂质的具体分布情况。
The four-probe measurement of thin-film conductance and anodizing de-layering were used to determine the specific distribution of phosphorus in silicon. At constant surface concentration, they deviate from the residual error distribution. If this is due to the fact that the diffusion coefficient is a function of the impurity concentration, a strong dependence of the diffusion coefficient with increasing impurity concentration is obtained experimentally when the impurity concentration is greater than 10-19 atoms / cm3. In the same way, the specific distribution of phosphorus diffused in silicon after silicon dioxide layer was measured, and the characteristics of the impurity distribution were studied. Experiments show that the oxide layers with different thickness still have masking effect at 1300 ℃, Near the time, the common feature of the impurity distribution is that the surface concentration is low (~10 ~ (17) atoms / cm ~ 3) and the junction is shallow (~1 μm). For different thicknesses of the oxide layer, after a sufficient time, the surface concentration in the silicon is not affected by the thickness of the oxide layer, but only by the vapor pressure of the diffusion source. The specific distribution of phosphorus through the oxide layer is also closely related to the nature and conditions of the diffusion source. The observed increase in oxide thickness during diffusion has the potential to affect the specific distribution of impurities near the surface.