利用低溫光激螢光光譜偵測半導體微量雜質濃度

Abstract

本實驗第一部分利用光激螢光光譜分析矽晶圓中微量III族或V族雜質的種類與濃度。在低溫低激發功率的條件下，可清楚觀察到自由激子發光以及受雜質原子吸引的束縛激子發光。其中束縛激子與自由激子發光強度的比值有隨雜質濃度上升而增加的特性，其關聯性相當接近於線性增加。透過標準樣品校正，我們測得雜質濃度介於1011~1014 cm-3間的螢光比例。藉由此方法，我們可分析未知樣品的雜質種類及濃度。論文第二部分利用光激螢光光譜與反射光譜量測氮化鎵中錳原子濃度與對其能隙的影響。首先我們利用光激螢光光譜觀察到自由激子能量有隨錳濃度上升而增加的現象，證明了p-d交換作用在此材料中扮演了關鍵角色。接著利用反射光譜可量得三價猛的吸收，我們發現其隨參雜濃度有線性上升的現象。

The species and concentration of trace III-V impurity in silicon wafers are determined by photoluminescence (PL). At low temperature and low excitation conditions, the emission of free exciton (FE) and impurity-bound exciton (BE) could be clearly observed. In particularly, the intensity ratio between BE and FE increases with increasing impurity concentration, having a correlation close to linear dependence. The intensity ratio for impurity concentration between 1011~1014 cm-3 have been measured using calibration samples, by which the impurity species and concentration in silicon wafers can be determined. In the second part, the Mn concentration in GaN is determined by reflectance spectra, and the impact of Mn on bandgap is measured by PL. First, the increasing FE energy with the increasing Mn concentration is observed by PL, indicating the p-d exchange interaction plays a very important role in this material. Then, the intra-atomic absorption of Mn3+ can be measured by reflectance spectra, the concentration of Mn3+ has a linear dependence on the Mn incorporation.