School of Electrical and Electronics Engineering, Nanyang Technological University, Singapore 639798, Singapore.
Temasek Laboratories @ NTU, Research Techno Plaza, 50 Nanyang Drive, Singapore 639798, Singapore.
Sensors (Basel). 2019 Nov 21;19(23):5107. doi: 10.3390/s19235107.
A low voltage (-20 V) operating high-energy (5.48 MeV) α-particle detector with a high charge collection efficiency (CCE) of approximately 65% was observed from the compensated (7.7 × 10 /cm) metalorganic vapor phase epitaxy (MOVPE) grown 15 µm thick drift layer gallium nitride (GaN) Schottky diodes on free-standing n+-GaN substrate. The observed CCE was 30% higher than the bulk GaN (400 µm)-based Schottky barrier diodes (SBD) at -20 V. This is the first report of α-particle detection at 5.48 MeV with a high CCE at -20 V operation. In addition, the detectors also exhibited a three-times smaller variation in CCE (0.12 %/V) with a change in bias conditions from -120 V to -20 V. The dramatic reduction in CCE variation with voltage and improved CCE was a result of the reduced charge carrier density (CCD) due to the compensation by Mg in the grown drift layer (DL), which resulted in the increased depletion width (DW) of the fabricated GaN SBDs. The SBDs also reached a CCE of approximately 96.7% at -300 V.
从补偿（7.7×10 /cm）的金属有机气相外延（MOVPE）生长的 15 µm 厚漂移层氮化镓（GaN）肖特基二极管上观察到具有约 65%的高电荷收集效率（CCE）的低电压（-20 V）工作的高能（5.48 MeV）α-粒子探测器。在-20 V 下，观察到的 CCE 比基于块状 GaN（400 µm）的肖特基势垒二极管（SBD）高出 30%。这是首次在 5.48 MeV 下以 -20 V 操作的高 CCE 进行α-粒子检测的报道。此外，探测器还表现出随着偏置条件从-120 V 变化到-20 V，CCE 的变化幅度小三倍（0.12 %/V）。由于生长漂移层（DL）中的 Mg 补偿导致载流子密度（CCD）降低，从而导致制造的 GaN SBD 的耗尽宽度（DW）增加，因此 CCE 随电压的变化明显减少，CCE 也得到了提高。SBD 还在-300 V 时达到了约 96.7%的 CCE。
