# US 2014/0153602 A1 · Semiconductor light emitting device having a p-type semiconductor layer with a p-type impurity > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153602 A1 - Document ID: US20140153602A1 - Status: Published application - Kind: A1 - Application number: 14/175,223 - Filed: 2014-02-07 - Published: 2014-06-05 - Earliest claimed: 2010-12-01 - Assignees: Kabushiki Kaisha Toshiba - Applicants: Kabushiki Kaisha Toshiba - Inventors: Koichi Tachibana; Hajime Nago; Toshiki Hikosaka; Shigeya Kimura; Shinya Nunoue - Web page: https://patentgrep.com/patent/US20140153602A1 ## CPC - H10H 20/8252: {characterised by the dopants} - H01S 5/32341: {blue laser based on GaN or GaP} - H10H 20/81: Bodies - H10H 20/825: containing nitrogen, e.g. GaN - H10H 20/832: characterised by their material - H10H 20/812: within the light-emitting regions, e.g. having quantum confinement structures - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL ## Abstract According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, a light emitting part, and a p-side electrode. The light emitting part is provided between the n-type and the p-type semiconductor layers, and includes a plurality of barrier layers and a plurality of well layers. The p-side electrode contacts the p-type semiconductor layer. The p-type semiconductor layer includes first, second, third, and fourth p-type layers. The first p-type layer contacts the p-side electrode. The second p-type layer contacts the light emitting part. The third p-type layer is provided between the first p-type layer and the second p-type layer. The fourth p-type layer is provided between the second p-type layer and the third p-type layer. The second p-type layer contains Al and contains a p-type impurity in a lower concentration lower than that in the first concentration. ## Claims ### Claim 1 A semiconductor light emitting device comprising: an n-type semiconductor layer; a p-type semiconductor layer; a light emitting part provided between the n-type semiconductor layer and the p-type semiconductor layer, the light emitting part including a plurality of barrier layers and a plurality of well layers, the well layers being provided between the barrier layers; and a p-side electrode contacting the p-type semiconductor layer, the p-type semiconductor layer including: a first p-type layer contacting the p-side electrode and containing a p-type impurity in a first concentration; a second p-type layer contacting the light emitting part, containing Al and containing a p-type impurity in a second concentration lower than the first concentration; a third p-type layer provided between the first p-type layer and the second p-type layer, the third p-type layer containing a p-type impurity in a third concentration lower than the second concentration; and a fourth p-type layer provided between the second p-type layer and the third p-type layer, the fourth p-type layer having a concentration of a p-type impurity decreasing from the second concentration to the third concentration along a first direction from the n-type semiconductor layer toward the p-type semiconductor layer. ### Claim 2 (depends on 1) The device according to claim 1, wherein the first concentration is 2×1020 cm−3 or more. ### Claim 3 (depends on 1) The device according to claim 1, wherein the second concentration is not less than 2.5×1019 cm−3 and less than 2×1020 cm−3. ### Claim 4 (depends on 1) The device according to claim 1, wherein the third concentration is not less than 1×1019 cm−3 and less than 2.5×1019 cm−3. ### Claim 5 (depends on 1) The device according to claim 1, wherein a difference between a thickness of the third p-type layer and a thickness of the fourth p-type layer is smaller than a difference between the thickness of the third p-type layer and a thickness of the first p-type layer, and smaller than the difference between the thickness of the third p-type layer and a thickness of the second p-type layer. ### Claim 6 (depends on 1) The device according to claim 1, wherein the thickness of the first p-type layer is smaller than a thickness of the third p-type layer, and smaller than a thickness of the fourth p-type layer. ### Claim 7 (depends on 1) The device according to claim 1, wherein a thickness of the second p-type layer is smaller than a thickness of the third p-type layer, and smaller than a thickness of the fourth p-type layer. ### Claim 8 (depends on 1) The device according to claim 1, wherein the first concentration is a concentration of Mg in the first p-type layer, the second concentration is a concentration of Mg in the second p-type layer, the third concentration is a concentration of Mg in the third p-type layer, and the concentration of the p-type impurity in the fourth p-type layer is a concentration of Mg in the fourth p-type layer. ### Claim 9 (depends on 1) The device according to claim 1, wherein a variation of the third concentration is within plus minus 20% of an average value of the third concentration. ### Claim 10 (depends on 1) The device according to claim 1, wherein the third concentration is not less than 0.05 times the second concentration and not more than 0.8 times the second concentration. ### Claim 11 (depends on 1) The device according to claim 1, wherein a Mg concentration in the fourth p-type layer decreases from a value of 2.5×1019 cm−3 or more to a values of less than 2.5×1019 cm−3 along the first direction. ### Claim 12 (depends on 1) The device according to claim 1, wherein a thickness of the first p-type layer is not less than 1 nanometer and less than 10 nanometers. ### Claim 13 (depends on 1) The device according to claim 1, wherein a thickness of the second p-type layer is not less than 1 nanometer and less than 10 nanometers. ### Claim 14 (depends on 1) The device according to claim 1, wherein a thickness of the third p-type layer is not less than 10 nanometers and not more than 80 nanometers. ### Claim 15 (depends on 1) The device according to claim 1, wherein a thickness of the fourth p-type layer is not less than 10 nanometers and not more than 80 nanometers. ### Claim 16 (depends on 1) The device according to claim 1, wherein the first p-type layer is a GaN layer, the third p-type layer is a GaN layer, and the fourth p-type layer is a GaN layer. ### Claim 17 (depends on 1) The device according to claim 1, wherein the p-side electrode includes a metal oxide and is translucent for light emitted from the light emitting part. ### Claim 18 (depends on 1) The device according to claim 1, wherein the well layer includes InGaN, and the barrier layer includes GaN. ### Claim 19 (depends on 1) The device according to claim 1, wherein a peak wavelength of light emitted from the light emitting part 40 is not less than 380 nanometers and not more than 550 nanometers. ### Claim 20 (depends on 1) The device according to claim 1, wherein at least one of the well layers contains In, and a composition ratio of In among Group III elements in the at least one of the well layers is not less than 0.05 and not more than 0.3.