第三代半導體氮化鎵生長於(111)面矽基板，因兩者晶格匹配度較高，所以可利用低溫成核層成長單晶結構，是業界常用規格，用於製造半導體功率元件、射頻元件和LED等；(100)面的矽基板，因其結構對稱特性，很適合用於製造COMS元件，然而將氮化鎵生長於(100)矽基板是相當不易的事情，因為其晶格差異(lattice mismatch)相當大，雖然已有許多實驗室透過某些方法比如基板接合法(wafer bonding)得到品質不錯的氮化鎵，但其製作過程相當繁瑣，所以簡化過程仍是大部分實驗所追求的方向。 二維電洞氣(two dimensional hole gas, 2DHG)可應用於氮化物電子元件。本實驗利用BN做為磊晶緩衝層，在Si(100)基板依序成長BN、GaN、AlGaN，並藉由霍爾量測確認電洞訊號，能帶模擬也可得到2DHG的結果。在加入AlN中間層後，拉曼量測顯示明顯的GaN訊號，但SEM表面的觀察結果是相當粗糙，若將AlN、GaN去除，直接將AlGaN成長於BN/Si(100)表面，可以得到平坦的表面、並維持2DHG結構。 ;The third-generation semiconductor GaN is generally grown on the substrate of Si(111). This is due to relatively small lattice mismatch between GaN and Si(111), comparing to the case on Si(100). GaN-on-Si is commonly used for power devices, radio frequency devices and LEDs. Si(100) substrate is very suitable for the manufacture of CMOS devices due to its mature fabrication in IC industry. However, growing GaN on Si(100) substrates is quite difficult because of the high lattice mismatch. Although GaN and Si(100) can be combined by wafer bonding, the production process is quite cumbersome. Direct growth of GaN on Si(100) can benefit the integration of GaN devices and CMOS technology. Two dimensional hole gas (2DHG) can be used for GaN electronic devices. In this study, AlGaN/GaN was grown on a (100) silicon substrate, with BN as the nucleation layer. We confirm the 2DHG formation by Hall measurements, and the structure is verified by band diagram simulation. After adding a thin AlN layer below GaN can produce a strong Raman signal of GaN, but the surface becomes quite rough under scanning electron microscopy. It is found that removing the layers of GaN and AlN, and direct growth of AlGaN/BN on Si(100) can maintain the 2DHG structure and flat surface.
