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DE-102016015971-B4 - METHOD FOR PRODUCING RECOMBINATION CENTERS IN A SEMICONDUCTOR ELEMENT

DE102016015971B4DE 102016015971 B4DE102016015971 B4DE 102016015971B4DE-102016015971-B4

Abstract

A process that exhibits: Implanting recombination center particles into a semiconductor body (100) via at least one contact hole (21) in an insulating layer (20) formed on the semiconductor body (100); Producing an electrically connected contact electrode (30) to the semiconductor body in the at least one contact hole (21); and Heating the semiconductor body (100) to diffuse the recombination center particles into the semiconductor body (100), wherein the production of the contact electrode comprises the production of a barrier layer (31) on sections of the semiconductor body (100) that are exposed in the at least one contact hole (21), wherein the barrier layer (31) is designed to prevent recombination center particles from diffusing out of the semiconductor body (100) and the procedure further exhibits: Establishing a sacrificial layer (51) at least on the isolation layer (20) prior to implanting the recombination center particles; and Removing the sacrificial layer (51) before producing the contact electrode (30).

Inventors

  • Wolfgang Jantscher
  • Werner Schustereder
  • Kurt Pekoll
  • Manfred Pippan
  • Andreas Riegler
  • Alexander BINTER
  • Oliver Blank
  • Ravi Keshav Joshi
  • Jürgen Steinbrenner
  • Waqas Mumtaz Syed
  • Petra Fischer

Assignees

  • INFINEON TECHNOLOGIES AUSTRIA AG

Dates

Publication Date
20260513
Application Date
20161222

Claims (13)

  1. Method comprising: implanting recombination center particles into a semiconductor body (100) via at least one contact hole (21) in an insulating layer (20) formed on the semiconductor body (100); The process comprises: producing a contact electrode (30) electrically connected to the semiconductor body in the at least one contact hole (21); and heating the semiconductor body (100) to diffuse the recombination center particles into the semiconductor body (100), wherein the production of the contact electrode comprises producing a barrier layer (31) on sections of the semiconductor body (100) that are exposed in the at least one contact hole (21), wherein the barrier layer (31) is configured to prevent recombination center particles from diffusing out of the semiconductor body (100); and wherein the process further comprises: producing a sacrificial layer (51) at least on the insulating layer (20) prior to implanting the recombination center particles; and removing the sacrificial layer (51) prior to producing the contact electrode (30).
  2. Procedure according to Claim 1 , in which the production of the sacrificial layer (51) involves the production of the sacrificial layer (51) on the insulating layer (20) and on the semiconductor body (100) in the contact hole (21).
  3. Procedure according to Claim 2 , in which the heating takes place before the removal of the sacrificial layer (51).
  4. Method according to any of the preceding claims, wherein the sacrificial layer (51) comprises an oxide layer.
  5. Procedure according to Claim 1 , in which the production of the contact electrode (30) further comprises: production of at least one electrode layer (32) on the barrier layer (31).
  6. Procedure according to Claim 5 , in which the heating takes place after the barrier layer (31) has been produced and before the at least one electrode layer (32) has been produced.
  7. Procedure according to Claim 1 , in which the heating takes place before the barrier layer (31) is produced.
  8. A method according to any of the preceding claims, further comprising: producing an implantation mask (52) on the insulating layer (20) prior to implanting the recombination center particles; and removing the implantation mask (52) after implanting the recombination center particles.
  9. Procedure according to one of the Claims 1 until 8 , wherein the semiconductor body (100) has a contact hole (110) adjacent to the at least one contact hole (21) in the insulating layer (20), and wherein the recombination center particles are implanted into the contact hole (110) of the semiconductor body (100).
  10. Procedure according to one of the Claims 1 until 8 , which further features: after implanting the recombination center particles and prior to producing the contact electrode (30): producing a contact hole (110) in the semiconductor body (100) adjacent to the at least one contact hole (21) in the insulating layer (20).
  11. Procedure according to Claim 10 , wherein the creation of the contact hole (110) in the semiconductor body (100) comprises the etching of the semiconductor body (100) using the insulating layer (20) as an etching mask.
  12. Procedure according to one of the Claims 1 until 11 , in which the heating of the semiconductor body (100) features a Rapid Thermal Annealing process.
  13. Procedure according to one of the Claims 1 until 11 , in which the heating of the semiconductor body (100) involves an oven process.

Description

This description generally relates to a method for manufacturing recombination centers in a power semiconductor device. Power semiconductor devices, such as power MOSFETs (metal oxide semiconductor field-effect transistors), power IGBTs (insulated gate bipolar transistors), power diodes, and power thyristors, are widely used in industrial, automotive, household appliance, and consumer electronics applications. A power semiconductor device comprises a drift region (which can also be called a base region) that primarily defines the reverse voltage withstand capability of the semiconductor device. A power semiconductor device can operate in bipolar conduction mode, in which a charge carrier plasma with charge carriers of one type (electrons or holes) and charge carriers of a complementary type is present in the drift region. For example, a MOSFET is in bipolar conduction mode when an internal body diode, formed by the drift region and an adjacent body region, is forward-biased and conducting. The charge carrier plasma is removed when the device transitions from the bipolar conduction state to the blocking state. The time required to remove the charge carrier plasma, that is, the time required for the device to transition from the bipolar conduction state to a blocking state, depends on the concentration of charge carriers forming the plasma. The charge carrier concentration, and thus the behavior of the semiconductor device when transitioning from the bipolar power state to the cutoff state, can be adjusted by creating recombination centers in the drift region. These recombination centers promote the recombination of electrons and holes in the drift region, thereby helping to regulate the plasma concentration. Creating recombination centers can involve introducing recombination center atoms, such as platinum atoms, into the drift region during the semiconductor device fabrication process. However, some of these recombination center atoms can diffuse out of the semiconductor body during a subsequent process and contaminate processing equipment. The US 8 558 308 B1 This describes a method for creating recombination centers in a semiconductor body. The method includes implanting recombination center particles into the semiconductor body through a contact hole in an insulating layer formed on the semiconductor body, creating a contact electrode in the contact hole, and heating the semiconductor body to diffuse the recombination center particles within it. Creating the contact electrode involves forming a barrier layer on portions of the semiconductor body exposed in the contact hole. This barrier layer is designed to prevent recombination center particles from diffusing out of the semiconductor body. The US 2016 / 0 027 891 A1 This describes a transistor device with a stack of layers arranged in a contact hole on a semiconductor body. The semiconductor body consists of silicon carbide (SiC). The layer stack comprises a main electrode layer, a barrier layer on the main electrode layer, and another electrode layer on top of the barrier layer. The main electrode layer is, for example, a titanium-aluminum-silicon alloy. The barrier layer comprises, for example, a titanium layer or a titanium-tungsten layer. The US 4 259 683 A describes a diode with a base layer that has recombination centers to adjust the charge carrier lifetime. The object underlying the invention is to provide a method by which recombination centers are produced in a semiconductor device and by which the risk of contamination of processing equipment is reduced. This problem is solved by a method according to claim 1. Examples are explained below using drawings. The drawings serve to illustrate certain principles, so only those aspects necessary for understanding these principles are shown. The drawings are not to scale. In the drawings, the same reference symbols denote the same features. 1A to 1D show an example of a method for creating recombination centers in a semiconductor body; 2A to 2B illustrate a modification of the one in the 1A to 1B illustrated procedure; 3A to 3B illustrate a further modification of the one in the 1A to 1D illustrated procedure; 4A to 4B illustrate yet another modification of the one in the 1A to 1D illustrated procedure; 5 illustrates a vertical sectional view of a section of a diode, which includes recombination centers and a contact electrode; 6 illustrates a vertical sectional view of a section of a MOSFET, which includes recombination centers and a contact electrode; 7 illustrates a vertical sectional view of a section of an IGBT, which includes recombination centers and a contact electrode; 8A to 8B Illustrating horizontal sectional views in different section planes of a MOSFET of the in 6 illustrated type; 9A to 9E illustrate an example of a process for fabricating active component regions and a gate electrode of a transistor cell prior to fabricating recombination centers; and 10 shows a vertical sectional view