Growth of Semiconductor Bulk Single Crystals

几乎所有的电子和光电子器件都需要单晶结构的半导体材料。这些材料被称为单晶，是通过称为晶体生长的凝固过程产生的。今天，大多数大块半导体单晶是通过被称为熔融/溶液技术的生长过程从液相生长出来的。这些生长技术是从手工技艺演变而来的，很大程度上依赖于经验和直觉。即使在今天，在大多数技术中也是如此。两次生产同样的晶体仍然是一个挑战。因此，申请人的研究工作集中在使这些晶体生长技术科学化，以便可以再生地生长出所需的高质量晶体。这是拟议研究计划的主要目标。在实现这一主要目标的方向上，拟议的研究计划将集中在：i)通过液相扩散（LPD）技术从锗侧生长出硅成分（浓度）高达40%的SixGe1-x（硅锗）单晶，ii) CdxZn1-xTe （CZT）的生长；使用锥形新型坩埚通过行热法（THM）获得具有均匀锌（Zn）成分的镉碲化锌单晶，以及iii)在不同温度水平下将硅（Si）溶解到锗（Ge）熔体中。通过研究在这些过程中发生的流体流动、液相（熔体）的传热传质和固相（生长晶体、进料）的传热传质，来确定均匀晶体组成、稳定的生长/溶解界面以及最有利的混合和杂质（掺杂剂）在液相/熔体中的传输的最佳生长条件。

Almost all electronic and optoelectronic devices need semiconducting materials of single crystalline structure. These materials are called single crystals, and are produced by a solidification process called crystal growth. Today, most bulk semiconductor single crystals are grown from the liquid phase by the growth processes known as the melt/solution techniques. These growth techniques have evolved from artisanship, relying very much on experience and intuition. Even today, this is the case in most techniques if not in all. The production of the same crystal twice is still a challenge. The applicant's research efforts have thus been focused on making these crystal growth techniques scientific so that the desired high quality crystals can be grown reproducibly. This is the main objective of the proposed research program.In the direction of achieving this main objective, the proposed research program will focus on: i) Growth of SixGe1-x (silicon germanium) single crystals from the germanium side by the Liquid Phase Diffusion (LPD) technique with higher silicon compositions (concentrations) up to 40%, ii) Growth of CdxZn1-xTe (CZT; cadmium zinc telluride) single crystals with uniform zinc (Zn) compositions by the Travelling Heater Method (THM) using tapered novel crucibles, and iii) Dissolution of silicon (Si) into germanium (Ge) melt at various temperature levels. Optimum growth conditions for uniform crystal composition, stable growth/dissolution interfaces, and most favorable mixing and impurity (dopant) transport in the liquid solution/melt will be determined by studying fluid flow, heat and mass transfer in the liquid phase (melt) and heat and mass transfer in the solid phases (grown crystal, feed)) occurring during these processes.