Semiconductor body and method for producing a semiconductor body

Abstract

A semiconductor body main include a III-V compound semiconductor material having a p-conductive region doped with a p-dopant. The p-conductive region may include at least one first section, one second section, and one third section. The second section may be arranged between the first and third sections. The second section may directly adjoin the first and third sections. An indium concentration of at least one of the sections differs from an indium concentration of the other two sections.

Claims

1. A semiconductor body comprising a III-V compound semiconductor material; wherein the semiconductor body comprises: a p-conductive region doped with a p-dopant, wherein the p-conductive region comprises at least one first section, at least one second section, and at least one third section; wherein the second section is arranged between the first section and the third section; wherein the second section is directly adjacent to the first and the third sections; wherein an indium concentration of the second section is higher than the indium concentrations of both of the other two sections; wherein the indium concentration of the second section is at least 1×10.sup.18 atoms per cm.sup.3 and wherein the first section, the second section, and the third section have different concentrations of the p-dopant.

2. The semiconductor body as claimed in claim 1, wherein the second section has a higher concentration of the p-dopant than the first section.

3. The semiconductor body as claimed in claim 1, wherein at least the first section or the third section has an indium concentration of at least 1×10.sup.17 atoms per cm.sup.3.

4. The semiconductor body as claimed in claim 1, wherein the second section has a higher concentration of the p-dopant than the third section.

5. The semiconductor body as claimed in claim 4, wherein the concentration of the p-dopant in the second section has a local maximum.

6. The semiconductor body as claimed in claim 1, wherein the concentration of the p-dopant in the p-conductive region has a rate of change of at least ±1E+21 atoms/cm.sup.3/μm perpendicularly to a main extent plane of the first section, the second section, and the third section.

7. The semiconductor body as claimed in claim 1, further comprising an active region, wherein the p-conductive region comprises an electron blocking layer; wherein the electron blocking layer is present on a side of the p-conductive region facing toward the active region; wherein the first section and/or the second section lie at least partially inside the electron blocking layer; wherein the first section is adjacent to the active region and the third section is adjacent to the second section; and wherein the first section and/or the second section have a higher concentration of the p-dopant than the active region adjacent to the electron blocking layer and the third section adjacent to the second section.

8. The semiconductor body as claimed in claim 1, further comprising an active region; wherein the p-conductive region comprises a p-contact layer; wherein the p-contact layer is present on a side of the p-conductive region facing away from the active region; and the second section lies at least partially inside the p-contact layer.

9. The semiconductor body as claimed in claim 1, wherein the p-dopant comprises magnesium.

10. A semiconductor body comprising a III-V compound semiconductor material; wherein the semiconductor body comprises: an active region; and a p-conductive region doped with a p-dopant, wherein the p-conductive region comprises at least one first section, at least one second section, and at least one third section; wherein the at least one second section is arranged between the at least one first section and the at least one third section; wherein the at least one second section is directly adjacent to the at least one first section and to the at least one third section; wherein the at least one first section is directly adjacent to the active region; wherein the at least one first section, the at least one second section and the at least one third section have different concentrations of the p-dopant; wherein an indium concentration of at least one of the at least one first section, the at least one second section, and the at least one third section is different to the indium concentration of the other sections; wherein the at least one second section has a higher indium concentration than the at least one first section; wherein the at least one second section has a higher p-dopant concentration than the at least one first section; and wherein the at least one third section has a lower p-dopant concentration than the at least one first section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the embodiments and figures, components which are the same or of the same type, or which have the same effect, are respectively provided with the same references. The elements represented and their size ratios with respect to one another are not to be regarded as to scale. Rather, individual elements, in particular layer thicknesses, may be represented exaggeratedly large for better understanding.

(2) FIGS. 1A, 1B and 1C show sectional views of a semiconductor body as described here and a profile of the magnesium and indium concentrations inside the active region and the p-conductive region;

(3) FIGS. 2, 3A and 3B show the indium concentration and the concentration of a p-dopant in a first, second and third section of a semiconductor body;

(4) FIGS. 4A and 5A show indium and p-dopant flow rates during a method for producing a semiconductor body;

(5) FIG. 4B and FIG. 5B show concentrations of the p-dopant and indium in a first, a second and a third section of a p-conductive region of a semiconductor body.

(6) Elements which are the same or of the same type, or which have the same effect, are provided with the same references in the figures. The figures and the size ratios of the elements represented in the figures with respect to one another are not to be regarded as true to scale, unless units are explicitly given. Rather, some elements may be represented exaggeratedly large for better representability and/or for better understanding.

DETAILED DESCRIPTION

(7) FIG. 1A shows a schematic sectional representation of a semiconductor body 1 as described here according to a first exemplary embodiment. The semiconductor body 1 is epitaxially grown on a carrier 50. The semiconductor body includes an n-conductive region 30, an active region 20 and a p-conductive region 10. For example, the semiconductor body is formed with a compound semiconductor material, in particular a III-V compound semiconductor material, for example a nitride compound semiconductor material. For example, the semiconductor body is adapted to emit electromagnetic radiation during intended operation.

(8) The p-conductive region 10 includes an electron blocking layer 11 on a side 10a facing toward the active region 20. The electron blocking layer 11 is, for example, adapted to reduce or prevent an electron flow from the active region into the p-conductive region during intended operation. Furthermore, the p-conductive region 10 includes a p-contact layer 12 on its side 10c facing away from the active region 20. The p-contact layer 12 is adapted, during intended operation, to be electrically conductively contacted and conduct positive charge carriers in the direction of the active region 20.

(9) Furthermore, FIG. 1A shows a graph in which the concentration C of indium I and of a p-dopant M is plotted along the growth direction X of the p-conductive region 10 and of the active region 20. The graph shows that indium is nominally present only in the active region 20. Furthermore, the semiconductor body 1 has a particularly high concentration M of the p-dopant in the region of the electron blocking layer 11 and in the region of the p-contact layer 12. In particular, the concentration of the p-dopant M has local maxima in the region of the electron blocking layer 11 and of the p-contact layer 12. The electron blocking layer 11 is present on a side of the p-conductive region 10 facing toward the active region 20. The first section (shown in FIG. 1B) and/or the second section (shown in FIG. 1B) lie at least partially inside the electron blocking layer 11, the second section having a greater maximum indium concentration I than the first section adjacent to the active region 20 and the third section (shown in FIG. 1B) adjacent to the second section. For example, the first section has a maximum thickness of 30 nm, in particular at most 5 nm.

(10) FIG. 1B shows a schematic sectional representation of a semiconductor body 1 as described here according to a second exemplary embodiment. The semiconductor body 1 differs from the semiconductor body 1 represented in FIG. 1A by the concentration of the p-dopant M and of indium I inside the p-conductive region 10. The p-conductive region 10 includes a first section 101, a second section 102 and a third section 103. The second section 102 is directly adjacent to the first 101 and the third 103 sections. The indium concentration I of the second section 102 is different to the indium concentration I of the first section 101 and of the third section 103. Furthermore, the first 101, the second 102 and the third 103 sections have different concentrations M of the p-dopant. For example, the p-dopant includes magnesium, and in particular the p-dopant is magnesium.

(11) Furthermore, the second section 102 has a higher indium concentration than the first section 101 and the second section 102 has a higher concentration M of the p-dopant than the third section 103. In particular, the p-conductive region 10 has a lower minimum concentration of the p-dopant M in the third section 103 than the semiconductor body 1 represented in FIG. 1A. Furthermore, the concentration of the p-dopant decreases at the transition from the second region 102 to the third region 103 in the growth direction X at least with a maximum magnitude rate of change of 1×10.sup.21 atoms per cm.sup.3 per μm.

(12) The first section and/or the second section lie at least partially inside the electron blocking layer, the second section having a greater maximum indium concentration than the first section adjacent to the active region and the third section adjacent to the second section. Furthermore, the first and/or second section has a higher concentration of the p-dopant than the active region adjacent to the electron blocking layer and the third section adjacent to the second section.

(13) FIG. 1C shows a schematic sectional representation of a semiconductor body 1 as described here according to a third exemplary embodiment. In contrast to the first and the second exemplary embodiments, the semiconductor body 1 has a different concentration of indium I and of the p-dopant M in the p-conductive region 10. The p-conductive region 10 includes a further first 101′, a further second 102′ and a further third 103′ section, which are arranged next to one another in the growth direction X. The further second 102′ and/or further third 103′ section are at least partially arranged in the region of the p-contact layer 12. In particular, the further second section 102′ has a higher concentration M of the p-dopant than the first further section 101′. Furthermore, the further second section 102′ has a higher indium concentration I than the further first section 101′. For example, the magnesium concentration M increases with a rate of change of at least 3×10.sup.21 atoms per cm.sup.3 per μm in the further first 101′ and/or further second 102′ section along the growth direction X. In particular, the rate of change is not constant. For example, the rate of change of the concentration of the p-dopant along the growth direction has a maximum value which is at least 3×10.sup.21 atoms per cm.sup.3 per μm.

(14) FIG. 2 shows a graph in which a concentration C of indium I and of a p-dopant M in a first 101, a second 102 and a third 103 section along the growth direction X are represented. In the first section 101, the concentration of the p-dopant M is between 8×10.sup.19 and 3×10.sup.19 atoms per cm.sup.3. The indium concentration I in the first section 101 is less than 1×10.sup.17 atoms per cm.sup.3. In the growth direction X, the indium concentration I increases from the first section 101 in the direction of the second section 102. In particular, the indium concentration I in the region of the second section 102 is greater than 1×10.sup.18 atoms per cm.sup.3. In the region in which the indium concentration I has an increase from 1×10.sup.18 atoms per cm.sup.3 to more than 1×10.sup.20 atoms per cm.sup.3, the magnesium concentration M increases from 3×10.sup.19 atoms per cm.sup.3 to 1×10.sup.20 atoms per cm.sup.3. For example, the indium concentration I is at least 1×10.sup.18 atoms per cm.sup.3 in the entire second section 102.

(15) Inside the second section 102, the concentration of the p-dopant M decreases from a concentration of 1×10.sup.20 atoms per cm.sup.3 to a concentration of less than 3×10.sup.18 atoms per cm.sup.3. In particular, the flow rate of the p-dopant is 0 liters per second during the epitaxial growth of the entire second section 102. Nevertheless, the magnesium concentration in the second section 102 initially increases in the growth direction X, since the incorporation of magnesium into the p-conductive region 10 is assisted by means of the increased indium concentration I. Therefore, p-dopant, in particular magnesium, which has accumulated on the surface of the semiconductor body 1 during the epitaxial growth is initially taken up into the region of the semiconductor body 1 grown during this time period. Since no further p-dopant is supplied to the process chamber during the growth of the second section 102, the concentration of the p-dopant decreases in the second section 102.

(16) Adjacent to the second section 102 is the third section 103, in which the indium concentration I is less than 1×10.sup.17 atoms per cm.sup.3. In the third section 103, the concentration of the p-dopant M increases in the growth direction X. In particular, p-dopant has been supplied to the process chamber during the epitaxial growth of the third section 103.

(17) In particular, the indium concentration may be specified in units different to the Y axis. For example, the indium concentration in the first section 101 and in the third section 103 is at most 0.01%. Furthermore, the indium concentration in the second section 102 is at least 2.5%, such as at least 3%.

(18) FIG. 3A shows a profile of an indium concentration I and of a concentration of the p-dopant M inside a p-conductive region 10 and an active region 20 of a semiconductor body 1. The concentration of the p-dopant M in the p-conductive region 10 is between 3×10.sup.19 and 3×10.sup.20 atoms per cm.sup.3. The indium concentration I in the p-conductive region 10 is substantially less than 1×10.sup.17 atoms per cm.sup.3.

(19) In a first section 101, the concentration of the p-dopant M increases to a value of about 8×10.sup.19 atoms per cm.sup.3. In a second section 102, the concentration of the p-dopant M decreases to a value of 3×10.sup.19 atoms per cm.sup.3. In the entire p-conductive region 10, the concentration of the p-dopant M is at least 3×10.sup.19 atoms per cm.sup.3. In the first 101, second 102 and in the third 103 sections, the indium concentration I is less than 1×10.sup.16 atoms per cm.sup.3.

(20) FIG. 3B shows the concentration of the p-dopant M and of indium I in a p-conductive region 10 and an active region 20. In contrast to the exemplary embodiment represented in FIG. 3A, in the p-conductive region 10 the incorporation of the p-dopant M is adapted in sections by means of the addition of indium I. In the second section 102, the indium concentration I is increased in relation to the first 101 and the third 103 sections. In particular, the indium concentration I in the second section 102 is at least 1×10.sup.18 atoms per cm.sup.3. In the first section 101, the concentration of the p-dopant is at most 5×10.sup.19 atoms per cm.sup.3. In the growth direction X, the magnesium concentration initially increases in the second section. Subsequently, the concentration of the p-dopant M decreases in the growth direction X from more than 9×10.sup.19 atoms per cm.sup.3 to less than 2×10.sup.19 atoms per cm.sup.3. For example, the maximum rate of change of the concentration of the p-dopant in the growth direction X is at least 3×10.sup.21 atoms per cm.sup.3 per μm.

(21) During the epitaxial growth of the second 102 and third 103 sections, nominally no p-dopant M is supplied to the process chamber. The fact that the concentration of the p-dopant M initially increases in the growth direction in the second section is attributable to the fact that the incorporation of the p-dopant, in particular magnesium, into the semiconductor body is improved by means of the increased indium concentration I. In a third section 103 adjacent to the second section 102, the indium concentration I is at most 1×10.sup.17 atoms per cm.sup.3. In the third section 103, the magnesium concentration M is at most 2×10.sup.19 atoms per cm.sup.3. In particular, the concentration of the p-dopant in the second section 102 has a local maximum.

(22) In particular, the indium concentration may be specified in units different to the Y axis. For example, the indium concentration in the first section 101 and in the third section 103 is at most 0.01%. Furthermore, the indium concentration in the second section 102 is at least 0.1%, such as at least 0.5%.

(23) FIG. 4A shows the flow rate of indium IF and the flow rate of the p-dopant MF during the epitaxial growth of a first section 101 during a first time period T1, of a second section 102 during a second time period T2 and of a third section 103 during a third time period T3. The second time period T2 lies chronologically between the first T1 and the third T3 time periods. For example, the indium is fed with a flow rate IF into a process chamber in the form of a gas containing indium or a liquid containing indium. In the process chamber, for example, the semiconductor body 1 is grown epitaxially. Furthermore, the p-dopant is fed with a flow rate MF into the process chamber in which the semiconductor body 1 is being epitaxially grown. In particular, a different indium flow rate IF is adjusted during one of the time periods than during the other two time periods. In the present case, a different indium flow rate IF is adjusted during the second time period T2 than during the first time period T1 and the third time period T3. In particular, the flow rates of the p-dopant MF and of indium IF are not represented relative to one another in FIG. 4A.

(24) During the first time period T1, the flow rate of the p-dopant MF is higher than during the second time period T2. For example, a flow rate of the p-dopant MF of 0 liters per second is adjusted during the second time period T2. Furthermore, the indium flow rate IF is lower during the first time period T1 than during the second time period T2. During the third time period T3, the flow rate of the p-dopant MF may be at least as great as the flow rate of the p-dopant MF during the second time period T2. During the third time period T3, the indium flow rate IF is lower than during the second time period T2. In particular, the indium flow rate IF during the third time period T3 is equally great as the indium flow rate IF during the first time period T1.

(25) FIG. 4B shows by way of example the concentration of indium and of the p-dopant inside the first 101, the second 102 and the third 103 section, which are epitaxially grown during a first time period T1, a second time period T2 and a third time period T3.

(26) In particular, the sections 101, 102, 103 of FIG. 4B have been grown in the time periods T1, T2, T3 represented in FIG. 4B. In the first section 101, the p-conductive region 10 has an almost constant concentration of indium I and of the p-dopant M. In the second section 102, the concentration of the p-dopant M initially increases in the growth direction X to a maximum value and subsequently falls below the value of the concentration of the p-dopant M in the first region 101. The increase in the concentration of the p-dopant M in the second section 102 is attributable to the fact that p-dopant M which has accumulated on the surface of the semiconductor body during the epitaxy method is incorporated better into the lattice structure of the semiconductor body with an increasing indium concentration I. During the second time period 102, more p-dopant M per unit time is incorporated in the semiconductor body 1 than is provided by means of the flow rate of the p-dopant MF during the second time period T2. The concentration of the p-dopant M therefore decreases in the growth direction X in the second section 102. In particular, the concentration of the p-dopant decreases at least with a maximum magnitude rate of change of 1×10.sup.21 atoms per cm.sup.3 per μm.

(27) In the third section 103, the indium concentration I decreases in the growth direction X. For example, the indium concentration I falls a value which is at most equally high as the value in the first region 101. In regions in which the indium concentration I decreases in the growth direction X, concentration of the p-dopant M also decreases in the growth direction X.

(28) In a similar way to FIG. 4A, FIG. 5A shows a production method for producing a semiconductor body 1, during which a p-conductive region 10 having at least one first 101, one second 102 and one third 103 section is epitaxially grown. In this case, the first section 101 is grown during a first time period T1, the second section 102 is grown during a second time period T2 and the third section 103 is grown during a third time period T3. In contrast to the exemplary embodiment represented in FIG. 4A, a higher flow rate of the p-dopant MF and a higher flow rate of indium IF are adjusted during the second time period T2 than during the first time period T1. Furthermore, a lower indium flow rate IF is adjusted during the third time period T3 than during the second time period T2, and an at least equally high flow rate of the p-dopant MF is adjusted during the third time period T3 as during the second time period T2.

(29) FIG. 5B shows the concentration C of a p-dopant M and indium I in a first 101, second 102 and third 103 section of a p-conductive region, which have been epitaxially grown during the first T1, the second T2 and the third T3 time periods that are represented in FIG. 5A. In the first section 101, the indium concentration I and the concentration of the p-dopant M are almost constant. In the second section 102, the indium concentration I increases in the growth direction X to a maximum value. The concentration C of the p-dopant M initially increases in the second section 102 with a low rate of change and subsequently with a high rate of change to a maximum value. In particular, the concentration of the p-dopant increases with a greater rate of change with an increasing indium content I. This is attributable to the fact that an increased indium content improves the incorporation of the p-dopant into the semiconductor body.

(30) In the third section 103, the indium concentration I decreases in the growth direction X. For example, the indium concentration I in the third section 103 decreases in the growth direction X to a value which corresponds to the indium concentration I in the first section 101. The concentration C of the p-dopant M in the third section 103 decreases in the growth direction X. This is attributable to the fact that the incorporation of the p-dopant M into the semiconductor body 1 becomes more difficult with a decreasing indium concentration I. The p-dopant M therefore accumulates more on the surface of the semiconductor body 1 during the epitaxial growth of the third section 103. The incorporation of the p-dopant M in the third section 103 decreases with decreasing indium concentration I.

(31) The description with the aid of the exemplary embodiments does not restrict the invention to said exemplary embodiments. Rather, the invention includes any new feature and any combination of features, which includes in particular any combination of features in the patent claims, even if this feature or this combination per se is not explicitly indicated in the patent claims or exemplary embodiments.

LIST OF REFERENCES

(32) 1 semiconductor body 10 p-conductive region 10a side of the p-conductive region facing toward the active region 10c side of the p-conductive region facing away from the active region 20 active region 30 n-conductive region 50 carrier 11 electron blocking layer 12 p-contact layer I indium M p-dopant C concentration 101 first section 101′ further first section 102 second section 102′ further second section 103 third section 103′ further third section T1 first time period T2 second time period T3 third time period X growth direction