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SUPPER-SENSITIVE IMAGING SENSORS USING AVALANCHE MULTIPLICATION PHOTOCONDUCTIVE FILMS AND MICR-FIELD-EMISSION CATHODE ARRAYS

使用雪崩倍增光导薄膜和微场发射阴极阵列的超灵敏成像传感器

基本信息

批准号：
07455149
负责人：
ANDO Takao
金额：
$ 2.24万
依托单位：
SHIZUOKA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

To realized the supper-sensitive imaging sensors, avalanche multiplication pin photodiode using amorphorus silicon films and micr-field-emission cathodes were investigated. As a result, the following facts become clear.1. The photocurrent amplification in a-Si : H films is caused by impact-ionization of electrons. The amplification gain is limited by carrier scattering effect under high temperature operation and by geminate-recombination mechanism under low temperature region, respectively. The boundary between these temperature regions is determined, depending upon the condition of a-Si : H films. 2. There is two dominant mechnisms as a origin of a dark current in a-Si : H films. One is to be generated through the interface states existing on the interface between silicon substrate and a-Si : H filme. The dark current has temperature dependence and dominates at low bias voltage. Another is tunnel current flowing through trap states lie across the fobidden gap of a-Si : H layr, that is dominant at high electric field. 3. p-type a-SiC : H/i-type a-Si _<1-x>C_x : H/n-type crystalline Si photodiode having conduction-band step DELTA E_c between a-Si_<1-x>C_x : H and crystalline Si is prepared and it is found that at DELTA E_c*0.4eV avalanche gain is two ; each electron assisted by conduction-band discontinuous impact-ionizes once after the conduction-band step. Moreover, three graded-gap supper lattice photodiode (a-Si : H/a-Si_<1-x>C_x : H structure) is studied and at DELTA E_c=0.45eV maximum photocurrent gain of 6.4 was obtained. 4. Novel vilcano type emitters deposited under well-contoroled pressure is investigated. maximum field emission current larger than 750nA was observed from the rims having daimeter of 5 mu m. The value of this emission current is enough to drive the imaging sensors.New, we hasten the implementation of supper-sensitive imaging sensors.

为了实现超灵敏图像传感器，研究了非晶硅薄膜雪崩倍增pin光电二极管和微场发射阴极。因此，以下事实变得清楚。a-Si：H薄膜中的光电流放大是由电子的碰撞电离引起的。在高温工作时，放大增益受载流子散射效应的限制;在低温工作时，放大增益受孪晶复合机制的限制。根据a-Si：H膜的条件确定了这些温度区之间的边界。2. a-Si：H薄膜中暗电流的产生有两种主要机制。一种是通过硅衬底与a-Si：H薄膜界面上存在的界面态产生的。暗电流具有温度依赖性，并且在低偏压下占主导地位。另一种是隧穿电流穿过陷阱态穿过a-Si：H层的fobidden间隙，在高电场下占主导地位。3. p型a-SiC：H/i型a-Si _<1-x>C_x：H/n型晶体Si光电二极管，在a-Si_ C_x：H之间具有导带阶跃Δ E_c<1-x>。在Δ E_c*0.4eV处，雪崩增益为2，每个电子在导带台阶后，在导带不连续的辅助下碰撞电离一次。此外，还研究了三阶带隙超晶格光电二极管（a-Si：H/a-Si_<1-x>C_x：H结构），在Δ E_c=0.45eV时，获得了6.4的最大光电流增益。4.研究了在良好控制的压力下沉积的新型vilcano型滴头。从直径为5 μ m的边缘观察到大于750 nA的最大场发射电流。该发射电流的值足以驱动成像传感器。新的，我们加快了超灵敏成像传感器的实施。