Detection method for sensitive parts of ionization damage in bipolar transistor

Patent metadata

Field	Value
Publication number	US-12153082-B2
Application number	US-202117626820-A
Country	US
Kind code	B2
Filing date	Jul 27, 2021
Priority date	Jul 28, 2020
Publication date	Nov 26, 2024
Grant date	Nov 26, 2024

Abstract

The present invention provides a detection method for sensitive parts of ionization damage in a bipolar transistor, which includes the following steps: selecting an irradiation source, and carrying out irradiation test on the bipolar transistor to be tested; installing the irradiated bipolar transistor on a test bench of a deep level transient spectroscopy system, and setting test parameters; selecting at least two different bias voltages, and testing the bipolar transistor to obtain a deep level transient spectrum; determining whether a defect is an ionization defect according to a peak position of the defect signal in the deep level transient spectrum; determining the defect type as oxidation trapped charges or an interface state according to the level of the defect signal in the deep level transient spectrum; and determining the sensitive area of ionization damage in the bipolar transistor according to the determination result of the defect signal type.

First claim

The invention claimed is:

1. A detection method for sensitive parts of ionization damage in a bipolar transistor, comprising the following steps:
step S 100 : selecting an irradiation source, and carrying out an irradiation test on a bipolar transistor to be tested;
step S 200 : installing the irradiated bipolar transistor on a test bench of a deep level transient spectroscopy system, and setting test parameters;
step S 300 : selecting at least two different bias voltages, and testing the bipolar transistor to obtain a deep level transient spectrum;
step S 400 : determining whether a defect signal is an ionization defect according to a peak position of the defect signal in the deep level transient spectrum;
step S 500 : determining a type of the defect signal as an oxidation trapped charge signal or an interface state signal according to a level of the defect signal in the deep level transient spectrum; and
step S 600 : determining a sensitive area of ionization damage in the bipolar transistor according to a determination result of the type of the defect signal;
wherein the step S 500 comprises:
a band gap of a collector region of the bipolar transistor is presented by Eg;
if the level of the defect signal is less than α*Eg, determining that the defect signal is the oxidation trapped charge signal; and
if the level of the defect signal is greater than α*Eg, determining that the defect signal is the interface state signal;
wherein α is a judgment parameter and is in a range of 0.2 to 0.5.

2. The detection method for sensitive parts of ionization damage in a bipolar transistor of claim 1 , wherein the step S 600 comprises:
if the defect signal only has the oxidation trapped charge signal, determining that the sensitive area of ionization damage in the bipolar transistor includes an oxide layer β1 above a neutral base region;
if the defect signal only has the interface state signal, determining that the sensitive area of ionization damage in the bipolar transistor includes an emitter junction surface β2 and a neutral base region surface β3; and
if the defect signal contains both the oxidation trapped charge signal and the interface state signal, determining that the sensitive area of ionization damage in the bipolar transistor includes the oxide layer β1, the emitter junction surface β2, and the neutral base region surface β3.

3. The detection method for sensitive parts of ionization damage in a bipolar transistor of claim 1 , wherein the step S 400 comprises:
if the peak position of the defect signal does not change with a change of the bias voltage, determining that the defect signal is an inherent defect; and
if the peak position of the defect signal shifts with the change of the bias voltage, determining that the defect signal is an ionization defect.

4. The detection method for sensitive parts of ionization damage in a bipolar transistor of claim 1 , wherein in the step S 100 , the irradiation source is selected from one of X-rays, gamma-rays, photons or neutrons.

5. The detection method for sensitive parts of ionization damage in a bipolar transistor of claim 1 , wherein in the step S 100 , the irradiation source includes charged particles.

6. The detection method for sensitive parts of ionization damage in a bipolar transistor of claim 5 , wherein the step S 100 comprises:
selecting the charged particles as the irradiation source;
calculating an incident depth of the charged particles in the bipolar transistor by adopting a Monte Carlo method to ensure that the incident depth is greater than a thickness of an oxide layer of the bipolar transistor;
calculating an ionizing absorbed dose I d and a displacement absorbed dose D d of the charged particles in the bipolar transistor by adopting the Monte Carlo method to ensure that log[(I d +D d )/D d ] is greater than 5; and
carrying out the irradiation test on the bipolar transistor.

7. The detection method for sensitive parts of ionization damage in a bipolar transistor of claim 1 , wherein in the step S 100 , a change rate of electrical performance parameters of the bipolar transistor is controlled to be greater than or equal to 20% during the irradiation test.

8. The detection method for sensitive parts of ionization damage in a bipolar transistor according to claim 1 , wherein in the step S 200 , the test parameters are as follows: a temperature scan range is 4K to 300K, a step size is 0.1K, a maximum reversed bias voltage V R is less than 50% of a rated voltage of the bipolar transistor, a pulse voltage is less than or equal to the maximum reversed bias voltage V R , and a pulse time is 1ns to 1s.

9. The detection method for sensitive parts of ionization damage in a bipolar transistor according to claim 8 , wherein in the step S 300 , a range of the bias voltage is 0.1*V R to V R , wherein V R is the maximum reversed bias voltage.

Assignees

• Harbin Inst Technology

Inventors

• Li Xingji
• Yang Jianqun
• Lv Gang
• Wei Yadong
• Xu Xiaodong
• Ying Tao
• Cui Xiuhai

Classifications

• G01R31/2608

  for testing bipolar transistors · CPC title

• G01R31/2648

  Characterising semiconductor materials (testing of materials or semi-finished products G01R31/2831; testing during manufacture H10P74/00) · CPC title

• G01R31/2653 Primary

  using electron beams · CPC title

• G01N23/02 Primary

  by transmitting the radiation through the material · CPC title