ICP刻蚀气压对碲镉汞电学性能的影响

Effects of ICP Etching Pressure on Electrical Properties of HgCdTe

研究了利用ICP(Inductively Coupled Plasma)干法刻蚀工艺制备长波碲镉汞光导器件过程中刻蚀气体压强对材料电学参数的影响。发现增大气体压强会导致材料的电学性能衰退,表现为材料的载流子浓度增加、迁移率降低以及电阻率增加。分析认为增大的压强使得材料内部产生了更多的填隙Hg离子,增强了载流子受到的电离杂质散射作用;同时材料内部也产生了更多的缺陷,极化声子散射作用也因此加强。由此解释了在流片过程中出现的某一批次碲镉汞光导器件性能的恶化是该批次器件ICP刻蚀工艺中的气压参数增加所致。

The effects of pressure during ICP dry etching on electrical parameters of long wavelength MCT photo-conductive detectors were studied.It is found that increased etching pressure can deteriorate the electric performance,in which the carrier concentration of MCT devices is increased,carrier mobility is decreased and the resistance is increased.It can be explained as more Hg interstitial is induced under higher pressure,carriers experience an enhanced ionization scattering,and also more defects appear due to the enhanced lattice scattering.It is proved that the deterioration of MCT detectors＇ performance is caused by higher pressure parameters during ICP etching.